diff --git a/packages/dnb-eufemia/src/extensions/forms/DataContext/Provider/__tests__/Provider.test.tsx b/packages/dnb-eufemia/src/extensions/forms/DataContext/Provider/__tests__/Provider.test.tsx
index a2e275a18e2..eb565927b62 100644
--- a/packages/dnb-eufemia/src/extensions/forms/DataContext/Provider/__tests__/Provider.test.tsx
+++ b/packages/dnb-eufemia/src/extensions/forms/DataContext/Provider/__tests__/Provider.test.tsx
@@ -1,4 +1,4 @@
-import React, { StrictMode, createRef, useContext } from 'react'
+import React, { StrictMode, createRef, useContext, useEffect } from 'react'
 import {
   act,
   fireEvent,
@@ -2214,8 +2214,12 @@ describe('DataContext.Provider', () => {
         </DataContext.Provider>
       )
 
-      expect(nestedMockData).toHaveLength(1)
-      expect(nestedMockData[0]).toEqual(initialData)
+      expect(nestedMockData).toHaveLength(3)
+      expect(nestedMockData).toEqual([
+        initialData,
+        initialData,
+        initialData,
+      ])
 
       const inputElement = document.querySelector('input')
       expect(inputElement).toHaveValue('bar')
@@ -2247,11 +2251,15 @@ describe('DataContext.Provider', () => {
         </>
       )
 
-      expect(sidecarMockData).toHaveLength(2)
-      expect(sidecarMockData).toEqual([undefined, initialData])
+      expect(sidecarMockData).toHaveLength(3)
+      expect(sidecarMockData).toEqual([
+        undefined,
+        initialData,
+        initialData,
+      ])
 
-      expect(nestedMockData).toHaveLength(1)
-      expect(nestedMockData).toEqual([initialData])
+      expect(nestedMockData).toHaveLength(2)
+      expect(nestedMockData).toEqual([initialData, initialData])
 
       const [sidecar, nested] = Array.from(
         document.querySelectorAll('input')
@@ -2260,6 +2268,58 @@ describe('DataContext.Provider', () => {
       expect(nested).toHaveValue('bar')
     })
 
+    it('should be able to update data from side car', async () => {
+      const sidecarMockData = []
+      const nestedMockData = []
+
+      const SidecarMock = () => {
+        const { data, update } = Form.useData(identifier)
+
+        useEffect(() => {
+          update('/fieldA', () => 'updated A')
+          update('/fieldB', () => 'updated B')
+        }, [update])
+
+        sidecarMockData.push(data)
+        return null
+      }
+
+      const NestedMock = () => {
+        const { data } = Form.useData(identifier)
+        nestedMockData.push(data)
+        return <Field.String path="/fieldB" />
+      }
+
+      render(
+        <>
+          <SidecarMock />
+          <DataContext.Provider id={identifier}>
+            <Field.String path="/fieldA" />
+            <NestedMock />
+          </DataContext.Provider>
+        </>
+      )
+
+      expect(sidecarMockData).toHaveLength(2)
+      expect(sidecarMockData).toEqual([
+        undefined,
+        { fieldA: 'updated A', fieldB: 'updated B' },
+      ])
+
+      expect(nestedMockData).toHaveLength(2)
+      expect(nestedMockData).toEqual([
+        undefined,
+        { fieldA: 'updated A', fieldB: 'updated B' },
+      ])
+
+      const [sidecar, nested] = Array.from(
+        document.querySelectorAll('input')
+      )
+
+      expect(sidecar).toHaveValue('updated A')
+      expect(nested).toHaveValue('updated B')
+    })
+
     it('should support StrictMode', async () => {
       const initialData = { foo: 'bar' }
       const sidecarMockData = []
diff --git a/packages/dnb-eufemia/src/extensions/forms/Form/data-context/useData.tsx b/packages/dnb-eufemia/src/extensions/forms/Form/data-context/useData.tsx
index 0ed23c8c7cf..b80836d3a24 100644
--- a/packages/dnb-eufemia/src/extensions/forms/Form/data-context/useData.tsx
+++ b/packages/dnb-eufemia/src/extensions/forms/Form/data-context/useData.tsx
@@ -87,7 +87,7 @@ export default function useData<Data>(
       pointer.set(existingData, path, newValue)
 
       // update provider
-      sharedDataRef.current.update(existingData)
+      sharedDataRef.current.extend(existingData)
     },
     []
   )
diff --git a/packages/dnb-eufemia/src/shared/helpers/useSharedState.tsx b/packages/dnb-eufemia/src/shared/helpers/useSharedState.tsx
index 4d4d5a99174..c5ff893fca4 100644
--- a/packages/dnb-eufemia/src/shared/helpers/useSharedState.tsx
+++ b/packages/dnb-eufemia/src/shared/helpers/useSharedState.tsx
@@ -39,7 +39,7 @@ export function useSharedState<Data>(
     }
   }, [hasMounted])
 
-  useLayoutEffect(() => {
+  useEffect(() => {
     if (waitForMountedRef.current) {
       forceUpdate()
     }
@@ -155,11 +155,6 @@ export function createSharedState<Data>(
 
     const get = () => sharedStates[id].data
 
-    const extend = (newData: Data) => {
-      sharedStates[id].data = { ...sharedStates[id].data, ...newData }
-      subscribers.forEach((subscriber) => subscriber())
-    }
-
     const set = (newData: Partial<Data>) => {
       sharedStates[id].data = { ...newData }
     }
@@ -169,8 +164,15 @@ export function createSharedState<Data>(
       subscribers.forEach((subscriber) => subscriber())
     }
 
+    const extend = (newData: Data) => {
+      sharedStates[id].data = { ...sharedStates[id].data, ...newData }
+      subscribers.forEach((subscriber) => subscriber())
+    }
+
     const subscribe = (subscriber: Subscriber) => {
-      subscribers.push(subscriber)
+      if (!subscribers.includes(subscriber)) {
+        subscribers.push(subscriber)
+      }
     }
 
     const unsubscribe = (subscriber: Subscriber) => {