Conversation Merge Does Not Complete Correctly

When I merge a couple of recorded conversations, the merge process takes a very long time or stays in the merging state for as long as the app remains open.

Steps to reproduce:

Record two or more conversations.

Select the conversations and start the merge process.

Go back to the conversation list.

The conversations remain in the merging state for a long time and may not complete while the app is open.

Close the app completely.

Reopen the app.

The merged conversation is now available, but the original separate conversations are still shown in the list.

Expected behavior: after the merge completes, the merged conversation should appear and the original conversations should no longer be shown separately.