ExchangeCtx: Fix issue with response timer cancellation (#26215)

* ExchangeCtx: Fix issue with response timer cancellation

* Add a boolean to record whether the message starts the reponse timer

src/messaging/ExchangeContext.cpp

@@ -156,6 +156,7 @@ CHIP_ERROR ExchangeContext::SendMessage(Protocols::Id protocolId, uint8_t msgTyp
     bool reliableTransmissionRequested =
         GetSessionHandle()->RequireMRP() && !sendFlags.Has(SendMessageFlags::kNoAutoRequestAck) && !IsGroupExchangeContext();
 
+    bool startedResponseTimer = false;
     // If a response message is expected...
     if (sendFlags.Has(SendMessageFlags::kExpectResponse) && !IsGroupExchangeContext())
     {
@@ -177,6 +178,7 @@ CHIP_ERROR ExchangeContext::SendMessage(Protocols::Id protocolId, uint8_t msgTyp
                 SetResponseExpected(false);
                 return err;
             }
+            startedResponseTimer = true;
         }
     }
 
@@ -217,8 +219,8 @@ CHIP_ERROR ExchangeContext::SendMessage(Protocols::Id protocolId, uint8_t msgTyp
 #if CONFIG_BUILD_FOR_HOST_UNIT_TEST
         }
 #endif
-
-        if (err != CHIP_NO_ERROR && IsResponseExpected())
+        // We should only cancel the response timer if the ExchangeContext fails to send the message that starts the response timer.
+        if (err != CHIP_NO_ERROR && startedResponseTimer)
         {
             CancelResponseTimer();
             SetResponseExpected(false);
@@ -267,8 +269,11 @@ void ExchangeContext::DoClose(bool clearRetransTable)
         mExchangeMgr->GetReliableMessageMgr()->ClearRetransTable(this);
     }
 
-    // Cancel the response timer.
-    CancelResponseTimer();
+    if (IsResponseExpected())
+    {
+        // Cancel the response timer.
+        CancelResponseTimer();
+    }
 }
 
 /**
@@ -590,12 +595,15 @@ CHIP_ERROR ExchangeContext::HandleMessage(uint32_t messageCounter, const Payload
         return CHIP_ERROR_INCORRECT_STATE;
     }
 
-    // Since we got the response, cancel the response timer.
-    CancelResponseTimer();
+    if (IsResponseExpected())
+    {
+        // Since we got the response, cancel the response timer.
+        CancelResponseTimer();
 
-    // If the context was expecting a response to a previously sent message, this message
-    // is implicitly that response.
-    SetResponseExpected(false);
+        // If the context was expecting a response to a previously sent message, this message
+        // is implicitly that response.
+        SetResponseExpected(false);
+    }
 
     // Don't send messages on to our delegate if our dispatch does not allow
     // those messages.