diff --git a/src/overlay/FlowControl.cpp b/src/overlay/FlowControl.cpp
index fe4c81adb7..0960259ee2 100644
--- a/src/overlay/FlowControl.cpp
+++ b/src/overlay/FlowControl.cpp
@@ -70,7 +70,7 @@ FlowControl::maybeReleaseCapacity(StellarMessage const& msg)
     releaseAssert(threadIsMain());
     std::lock_guard<std::mutex> guard(mFlowControlMutex);
 
-    if (msg.type() == SEND_MORE || msg.type() == SEND_MORE_EXTENDED)
+    if (msg.type() == SEND_MORE_EXTENDED)
     {
         if (mNoOutboundCapacity)
         {
@@ -283,8 +283,8 @@ FlowControl::canRead() const
 uint32_t
 FlowControl::getNumMessages(StellarMessage const& msg)
 {
-    return msg.type() == SEND_MORE ? msg.sendMoreMessage().numMessages
-                                   : msg.sendMoreExtendedMessage().numMessages;
+    releaseAssert(msg.type() == SEND_MORE_EXTENDED);
+    return msg.sendMoreExtendedMessage().numMessages;
 }
 
 bool
@@ -294,10 +294,7 @@ FlowControl::isSendMoreValid(StellarMessage const& msg,
     releaseAssert(threadIsMain());
     std::lock_guard<std::mutex> guard(mFlowControlMutex);
 
-    bool sendMoreExtendedType = msg.type() == SEND_MORE_EXTENDED;
-    bool sendMoreType = msg.type() == SEND_MORE;
-
-    if (!sendMoreExtendedType && !sendMoreType)
+    if (msg.type() != SEND_MORE_EXTENDED)
     {
         errorMsg =
             fmt::format("unexpected message type {}",
diff --git a/src/overlay/FlowControlCapacity.cpp b/src/overlay/FlowControlCapacity.cpp
index 69d2f66bcf..ec86fab896 100644
--- a/src/overlay/FlowControlCapacity.cpp
+++ b/src/overlay/FlowControlCapacity.cpp
@@ -36,7 +36,7 @@ void
 FlowControlMessageCapacity::releaseOutboundCapacity(StellarMessage const& msg)
 {
     ZoneScoped;
-    releaseAssert(msg.type() == SEND_MORE || msg.type() == SEND_MORE_EXTENDED);
+    releaseAssert(msg.type() == SEND_MORE_EXTENDED);
     auto numMessages = FlowControl::getNumMessages(msg);
     if (!hasOutboundCapacity(msg) && numMessages != 0)
     {
diff --git a/src/overlay/test/OverlayTests.cpp b/src/overlay/test/OverlayTests.cpp
index 26365c6058..91017e0d77 100644
--- a/src/overlay/test/OverlayTests.cpp
+++ b/src/overlay/test/OverlayTests.cpp
@@ -562,6 +562,15 @@ TEST_CASE("loopback peer flow control activation", "[overlay][flowcontrol]")
                 conn.getAcceptor()->sendSendMore(0, 0);
                 dropReason = "invalid message SEND_MORE_EXTENDED";
             }
+            SECTION("invalid message type")
+            {
+                // Manually construct a SEND_MORE message and send it
+                auto m = std::make_shared<StellarMessage>();
+                m->type(SEND_MORE);
+                m->sendMoreMessage().numMessages = 1;
+                conn.getAcceptor()->sendAuthenticatedMessageForTesting(m);
+                dropReason = "unexpected message type SEND_MORE";
+            }
             testutil::crankSome(clock);
             REQUIRE(!conn.getInitiator()->isConnectedForTesting());
             REQUIRE(!conn.getAcceptor()->isConnectedForTesting());