diff --git a/src/components/core/CoreManager.cpp b/src/components/core/CoreManager.cpp
index a740db8c4..9ec2caab2 100644
--- a/src/components/core/CoreManager.cpp
+++ b/src/components/core/CoreManager.cpp
@@ -94,15 +94,18 @@ shared_ptr<ChatModel> CoreManager::getChatModelFromSipAddress (const QString &si
 
   // Create a new chat model.
   if (!mChatModels.contains(sipAddress)) {
-    Q_ASSERT(mCore->createAddress(::Utils::appStringToCoreString(sipAddress)) != nullptr);
+    Q_CHECK_PTR(mCore->createAddress(::Utils::appStringToCoreString(sipAddress)));
 
-    auto deleter = [this](ChatModel *chatModel) {
-        mChatModels.remove(chatModel->getSipAddress());
-        delete chatModel;
-      };
+    // Don't use chatModel->getSipAddress() in lambda.
+    // If it is a migration chat room the chat room sip address can be changed!!!
+    auto deleter = [this, sipAddress](ChatModel *chatModel) {
+      bool removed = mChatModels.remove(sipAddress);
+      Q_ASSERT(removed);
+      delete chatModel;
+    };
 
     shared_ptr<ChatModel> chatModel(new ChatModel(sipAddress), deleter);
-    mChatModels[chatModel->getSipAddress()] = chatModel;
+    mChatModels[sipAddress] = chatModel;
 
     emit chatModelCreated(chatModel);
 
@@ -111,7 +114,7 @@ shared_ptr<ChatModel> CoreManager::getChatModelFromSipAddress (const QString &si
 
   // Returns an existing chat model.
   shared_ptr<ChatModel> chatModel = mChatModels[sipAddress].lock();
-  Q_CHECK_PTR(chatModel.get());
+  Q_CHECK_PTR(chatModel);
   return chatModel;
 }
 
diff --git a/src/components/core/CoreManager.hpp b/src/components/core/CoreManager.hpp
index 8ada943bf..d8f5f2e64 100644
--- a/src/components/core/CoreManager.hpp
+++ b/src/components/core/CoreManager.hpp
@@ -163,7 +163,7 @@ private:
   SettingsModel *mSettingsModel = nullptr;
   AccountSettingsModel *mAccountSettingsModel = nullptr;
 
-  QHash<QString, std::weak_ptr<ChatModel> > mChatModels;
+  QHash<QString, std::weak_ptr<ChatModel>> mChatModels;
 
   QTimer *mCbsTimer = nullptr;