diff --git a/core/lib/external_sign_in.ex b/core/lib/external_sign_in.ex
index ee5885c70..410dda794 100644
--- a/core/lib/external_sign_in.ex
+++ b/core/lib/external_sign_in.ex
@@ -11,7 +11,9 @@ defmodule ExternalSignIn do
         register_user(organisation, external_id)
       end
 
-    CoreWeb.UserAuth.log_in_user_without_redirect(conn, user)
+    conn
+    |> CoreWeb.UserAuth.log_in_user_without_redirect(user)
+    |> Plug.Conn.assign(:current_user, user)
   end
 
   def get_user_by_external_id(external_id) do
diff --git a/core/priv/gettext/en/LC_MESSAGES/eyra-consent.po b/core/priv/gettext/en/LC_MESSAGES/eyra-consent.po
index 514c23985..4434c6ee2 100644
--- a/core/priv/gettext/en/LC_MESSAGES/eyra-consent.po
+++ b/core/priv/gettext/en/LC_MESSAGES/eyra-consent.po
@@ -22,3 +22,11 @@ msgstr "<div>Write here your custom consent terms and conditions..</div>"
 #, elixir-autogen, elixir-format
 msgid "onboarding.consent.checkbox"
 msgstr "I have read and agree with the above terms"
+
+#, elixir-autogen, elixir-format
+msgid "locked.error.message"
+msgstr "This version of the consent text has already been signed by participants. Please refresh the page to continue changing the text."
+
+#, elixir-autogen, elixir-format
+msgid "out_of_sync.error.message"
+msgstr "Someone made changes to the consent text. Please refresh the page to continue."
diff --git a/core/priv/gettext/eyra-consent.pot b/core/priv/gettext/eyra-consent.pot
index 3c1fbcac2..d789ea5e9 100644
--- a/core/priv/gettext/eyra-consent.pot
+++ b/core/priv/gettext/eyra-consent.pot
@@ -22,3 +22,11 @@ msgstr ""
 #, elixir-autogen, elixir-format
 msgid "onboarding.consent.checkbox"
 msgstr ""
+
+#, elixir-autogen, elixir-format
+msgid "locked.error.message"
+msgstr ""
+
+#, elixir-autogen, elixir-format
+msgid "out_of_sync.error.message"
+msgstr ""
diff --git a/core/priv/gettext/nl/LC_MESSAGES/eyra-consent.po b/core/priv/gettext/nl/LC_MESSAGES/eyra-consent.po
index 37ca4e1e4..ae40207e9 100644
--- a/core/priv/gettext/nl/LC_MESSAGES/eyra-consent.po
+++ b/core/priv/gettext/nl/LC_MESSAGES/eyra-consent.po
@@ -22,3 +22,11 @@ msgstr "<div>Beschrijf hier de consent voorwaarden</div>"
 #, elixir-autogen, elixir-format
 msgid "onboarding.consent.checkbox"
 msgstr "Ik heb de bovenstaande voorwaarden gelezen en ga ermee akkoord"
+
+#, elixir-autogen, elixir-format
+msgid "locked.error.message"
+msgstr "Deze versie van de consent tekst is al ondertekend door participanten. Ververs de pagina om verdere aanpassingen te maken aan de tekst."
+
+#, elixir-autogen, elixir-format
+msgid "out_of_sync.error.message"
+msgstr "Iemand heeft de consent tekst is aangepast. Ververs de pagina om verder te gaan."
diff --git a/core/systems/assignment/crew_page_builder.ex b/core/systems/assignment/crew_page_builder.ex
index a1d79b86e..1206d2daf 100644
--- a/core/systems/assignment/crew_page_builder.ex
+++ b/core/systems/assignment/crew_page_builder.ex
@@ -13,44 +13,54 @@ defmodule Systems.Assignment.CrewPageBuilder do
   end
 
   defp flow(%{status: status} = assignment, assigns) do
-    if is_tester?(assignment, assigns) or status == :online do
-      flow(assignment, assigns, current_flow(assigns))
+    is_tester? = is_tester?(assignment, assigns)
+
+    if is_tester? or status == :online do
+      flow(assignment, assigns, current_flow(assigns), is_tester?)
     else
       []
     end
   end
 
-  defp flow(assignment, assigns, nil), do: full_flow(assignment, assigns)
+  defp flow(assignment, assigns, nil, is_tester?), do: full_flow(assignment, assigns, is_tester?)
 
-  defp flow(assignment, assigns, current_flow) do
-    full_flow(assignment, assigns)
+  defp flow(assignment, assigns, current_flow, is_tester?) do
+    full_flow(assignment, assigns, is_tester?)
     |> Enum.filter(fn %{ref: %{id: id}} ->
       Enum.find(current_flow, &(&1.ref.id == id)) != nil
     end)
   end
 
-  defp full_flow(assignment, assigns) do
+  defp full_flow(assignment, assigns, is_tester?) do
     [
-      consent_view(assignment, assigns),
-      work_view(assignment, assigns)
+      consent_view(assignment, assigns, is_tester?),
+      work_view(assignment, assigns, is_tester?)
     ]
     |> Enum.filter(&(&1 != nil))
   end
 
   defp current_flow(%{fabric: %{children: children}}), do: children
 
-  defp consent_view(%{consent_agreement: nil}, _), do: nil
+  defp consent_view(%{consent_agreement: nil}, _, _), do: nil
 
-  defp consent_view(%{consent_agreement: consent_agreement}, %{current_user: user, fabric: fabric}) do
-    revision = Consent.Public.latest_revision(consent_agreement, [:signatures])
+  defp consent_view(
+         %{consent_agreement: consent_agreement},
+         %{current_user: user, fabric: fabric},
+         is_tester?
+       ) do
+    if Consent.Public.has_signature(consent_agreement, user) and not is_tester? do
+      nil
+    else
+      revision = Consent.Public.latest_revision(consent_agreement, [:signatures])
 
-    Fabric.prepare_child(fabric, :onboarding_view, Assignment.OnboardingConsentView, %{
-      revision: revision,
-      user: user
-    })
+      Fabric.prepare_child(fabric, :onboarding_view, Assignment.OnboardingConsentView, %{
+        revision: revision,
+        user: user
+      })
+    end
   end
 
-  defp work_view(assignment, %{fabric: fabric} = assigns) do
+  defp work_view(assignment, %{fabric: fabric} = assigns, _) do
     work_items = work_items(assignment, assigns)
 
     Fabric.prepare_child(fabric, :work_view, Assignment.CrewWorkView, %{
@@ -84,7 +94,7 @@ defmodule Systems.Assignment.CrewPageBuilder do
     if task = Crew.Public.get_task(crew, identifier) do
       task
     else
-      Crew.Public.create_task(crew, [member], identifier)
+      Crew.Public.create_task!(crew, [member], identifier)
     end
   end
 end
diff --git a/core/systems/assignment/gdpr_form.ex b/core/systems/assignment/gdpr_form.ex
index 856fb6784..fd60d3600 100644
--- a/core/systems/assignment/gdpr_form.ex
+++ b/core/systems/assignment/gdpr_form.ex
@@ -48,7 +48,7 @@ defmodule Systems.Assignment.GdprForm do
     %{
       module: Consent.RevisionForm,
       params: %{
-        entity: Consent.Public.latest_unlocked_revision_safe(consent_agreement)
+        entity: Consent.Public.latest_revision(consent_agreement)
       }
     }
   end
diff --git a/core/systems/consent/_public.ex b/core/systems/consent/_public.ex
index 3a16c0ce1..87d95a68f 100644
--- a/core/systems/consent/_public.ex
+++ b/core/systems/consent/_public.ex
@@ -21,12 +21,37 @@ defmodule Systems.Consent.Public do
     |> Ecto.Changeset.put_assoc(:auth_node, auth_node)
   end
 
-  def create_revision(source, agreement) do
-    prepare_revision(source, agreement)
+  def bump_revision_if_needed(agreement_id) when is_integer(agreement_id) do
+    agreement_id
+    |> get_agreement!()
+    |> bump_revision_if_needed()
+  end
+
+  def bump_revision_if_needed(agreement) do
+    Multi.new()
+    |> Multi.run(:revision, fn _, _ ->
+      case latest_revision(agreement, [:signatures]) do
+        nil -> create_revision(agreement, dgettext("eyra-consent", "default.consent.text"))
+        %{source: source, signatures: [_ | _]} -> create_revision(agreement, source)
+        revision -> {:ok, revision}
+      end
+    end)
+    |> Repo.transaction()
+  end
+
+  def bump_revision_if_needed!(agreement) do
+    case bump_revision_if_needed(agreement) do
+      {:ok, %{revision: revision}} -> revision
+      _ -> nil
+    end
+  end
+
+  def create_revision(agreement, source) do
+    prepare_revision(agreement, source)
     |> Repo.insert()
   end
 
-  def prepare_revision(source, agreement) when is_binary(source) do
+  def prepare_revision(agreement, source) when is_binary(source) do
     %Consent.RevisionModel{}
     |> Consent.RevisionModel.changeset(%{source: source})
     |> Ecto.Changeset.put_assoc(:agreement, agreement)
@@ -52,8 +77,19 @@ defmodule Systems.Consent.Public do
     Repo.get!(Consent.RevisionModel, id) |> Repo.preload(preload)
   end
 
-  def has_signature(revision, user) do
-    get_signature(revision, user) != nil
+  def has_signature(context, user) do
+    get_signature(context, user) != nil
+  end
+
+  def get_signature(%Consent.AgreementModel{id: agreement_id}, %Core.Accounts.User{id: user_id}) do
+    from(s in Consent.SignatureModel,
+      join: r in Consent.RevisionModel,
+      on: r.id == s.revision_id,
+      where: s.user_id == ^user_id,
+      where: r.agreement_id == ^agreement_id
+    )
+    |> Repo.all()
+    |> List.first()
   end
 
   def get_signature(%Consent.RevisionModel{id: revision_id}, %Core.Accounts.User{id: user_id}) do
@@ -74,25 +110,6 @@ defmodule Systems.Consent.Public do
     |> Repo.all()
   end
 
-  def latest_unlocked_revision_safe(agreement, preload \\ []) do
-    if revision = latest_unlocked_revision(agreement, preload) do
-      revision
-    else
-      source =
-        if revision = latest_revision(agreement, preload) do
-          revision.source
-        else
-          dgettext("eyra-consent", "default.consent.text")
-        end
-
-      create_revision(source, agreement)
-    end
-
-    query_unlocked_revisions(agreement, preload)
-    |> Repo.all()
-    |> List.first()
-  end
-
   def latest_unlocked_revision(agreement, preload \\ []) do
     query_unlocked_revisions(agreement, preload)
     |> Repo.all()
@@ -134,13 +151,19 @@ defmodule Systems.Consent.Public do
         %Ecto.Changeset{data: %Consent.RevisionModel{id: id, updated_at: updated_at}} = changeset
       ) do
     Multi.new()
-    |> Multi.run(:validate_timestamp, fn _, _ ->
-      %{updated_at: stored_updated_at} = Consent.Public.get_revision!(id)
+    |> Multi.run(:validate, fn _, _ ->
+      %{updated_at: stored_updated_at, signatures: signatures} =
+        Consent.Public.get_revision!(id, [:signatures])
+
+      cond do
+        stored_updated_at != updated_at ->
+          {:error, :out_of_sync}
 
-      if stored_updated_at == updated_at do
-        {:ok, :valid}
-      else
-        {:error, "Revision out of sync"}
+        not Enum.empty?(signatures) ->
+          {:error, :locked}
+
+        true ->
+          {:ok, :valid}
       end
     end)
     |> Multi.update(:consent_revision, changeset)
@@ -150,10 +173,32 @@ defmodule Systems.Consent.Public do
 end
 
 defimpl Core.Persister, for: Systems.Consent.RevisionModel do
+  import CoreWeb.Gettext
+
   def save(_revision, changeset) do
     case Systems.Consent.Public.update_revision(changeset) do
-      {:ok, %{consent_revision: revision}} -> {:ok, revision}
-      _ -> {:error, changeset}
+      {:ok, %{consent_revision: revision}} ->
+        {:ok, revision}
+
+      {:error, _, _, _} = error ->
+        {:error, changeset |> handle_error(error)}
     end
   end
+
+  defp handle_error(changeset, {:error, :validate, :locked, _}) do
+    Systems.Consent.Public.bump_revision_if_needed!(changeset.data.agreement_id)
+
+    changeset
+    |> Ecto.Changeset.add_error(:locked, dgettext("eyra-consent", "locked.error.message"))
+  end
+
+  defp handle_error(changeset, {:error, :validate, :out_of_sync, _}) do
+    changeset
+    |> Ecto.Changeset.add_error(
+      :out_of_sync,
+      dgettext("eyra-consent", "out_of_sync.error.message")
+    )
+  end
+
+  defp handle_error(changeset, _), do: changeset
 end
diff --git a/core/systems/consent/revision_form.ex b/core/systems/consent/revision_form.ex
index 419359bb3..cad4c5035 100644
--- a/core/systems/consent/revision_form.ex
+++ b/core/systems/consent/revision_form.ex
@@ -48,12 +48,23 @@ defmodule Systems.Consent.RevisionForm do
         |> assign(entity: entity)
         |> flash_persister_saved()
 
-      {:error, _} ->
-        socket
-        |> flash_persister_error(dgettext("eyra-consent", "consent-out-of-sync-error"))
+      {:error, changeset} ->
+        socket |> handle_save_errors(changeset)
     end
   end
 
+  defp handle_save_errors(socket, %{errors: errors}) do
+    handle_save_errors(socket, errors)
+  end
+
+  defp handle_save_errors(socket, [{_, {message, _}} | _]) do
+    socket |> flash_persister_error(message)
+  end
+
+  defp handle_save_errors(socket, _) do
+    socket |> flash_persister_error()
+  end
+
   @impl true
   def render(assigns) do
     ~H"""
diff --git a/core/test/systems/consent/_public_test.exs b/core/test/systems/consent/_public_test.exs
index 2426f3e92..b41ed419f 100644
--- a/core/test/systems/consent/_public_test.exs
+++ b/core/test/systems/consent/_public_test.exs
@@ -18,10 +18,10 @@ defmodule Systems.Consent.PublicTest do
       Multi.new()
       |> Multi.insert(:agreement, Consent.Public.prepare_agreement(Authorization.prepare_node()))
       |> Multi.insert(:revision1, fn %{agreement: agreement} ->
-        Consent.Public.prepare_revision("revision1", agreement)
+        Consent.Public.prepare_revision(agreement, "revision1")
       end)
       |> Multi.insert(:revision2, fn %{agreement: agreement} ->
-        Consent.Public.prepare_revision("revision2", agreement)
+        Consent.Public.prepare_revision(agreement, "revision2")
       end)
       |> Repo.transaction()
 
@@ -48,7 +48,7 @@ defmodule Systems.Consent.PublicTest do
       Multi.new()
       |> Multi.insert(:agreement, Consent.Public.prepare_agreement(Authorization.prepare_node()))
       |> Multi.insert(:revision1, fn %{agreement: agreement} ->
-        Consent.Public.prepare_revision("revision1", agreement)
+        Consent.Public.prepare_revision(agreement, "revision1")
       end)
       |> Multi.insert(:signatureA1, fn %{revision1: revision1} ->
         Consent.Public.prepare_signature(revision1, user_a)
@@ -57,7 +57,7 @@ defmodule Systems.Consent.PublicTest do
         Consent.Public.prepare_signature(revision1, user_b)
       end)
       |> Multi.insert(:revision2, fn %{agreement: agreement} ->
-        Consent.Public.prepare_revision("revision2", agreement)
+        Consent.Public.prepare_revision(agreement, "revision2")
       end)
       |> Multi.insert(:signatureA2, fn %{revision2: revision2} ->
         Consent.Public.prepare_signature(revision2, user_a)
@@ -120,26 +120,25 @@ defmodule Systems.Consent.PublicTest do
     assert Consent.Public.latest_unlocked_revision(agreement, [:agreement]) == nil
   end
 
-  test "latest_unlocked_revision_safe/2 returns new revision in empty agreement" do
+  test "bump_revision_if_needed!/1 returns first revision" do
     agreement = Factories.insert!(:consent_agreement)
 
     assert %Systems.Consent.RevisionModel{
-             source: "<div>Beschrijf hier de consent voorwaarden</div>",
-             signatures: []
-           } = Consent.Public.latest_unlocked_revision_safe(agreement, [:signatures])
+             source: "<div>Beschrijf hier de consent voorwaarden</div>"
+           } = Consent.Public.bump_revision_if_needed!(agreement)
   end
 
-  test "latest_unlocked_revision_safe/2 returns latest revision" do
+  test "bump_revision_if_needed!/1 returns latest revision" do
     agreement = Factories.insert!(:consent_agreement)
-    _revision = Factories.insert!(:consent_revision, %{agreement: agreement, source: "source"})
+    %{id: id} = Factories.insert!(:consent_revision, %{agreement: agreement, source: "source"})
 
     assert %Systems.Consent.RevisionModel{
-             source: "source",
-             signatures: []
-           } = Consent.Public.latest_unlocked_revision_safe(agreement, [:signatures])
+             id: ^id,
+             source: "source"
+           } = Consent.Public.bump_revision_if_needed!(agreement)
   end
 
-  test "latest_unlocked_revision_safe/2 returns new revision on top of locked revision" do
+  test "bump_revision_if_needed!/1 returns new revision on top of locked revision" do
     user = Factories.insert!(:member)
 
     agreement = Factories.insert!(:consent_agreement)
@@ -148,9 +147,8 @@ defmodule Systems.Consent.PublicTest do
 
     assert %Systems.Consent.RevisionModel{
              id: revision_2_id,
-             source: "source",
-             signatures: []
-           } = Consent.Public.latest_unlocked_revision_safe(agreement, [:signatures])
+             source: "source"
+           } = Consent.Public.bump_revision_if_needed!(agreement)
 
     assert revision_1.id != revision_2_id
   end