I checked and if I'm correct the same thing is happening for last 3 builds. I'm not able to replicate it, however it looks like you are receiving message at the same time you switch view and this causes inconsistency during loading items to display (insert is done between reads) and causes exception.

I'm going to replace direct reads from memory with reads from cache which will be refreshed at once. This way, changes to database during reloading of table will not cause any inconsistencies.

I've rewritten chats list controller as I'm expecting it to cause issues. New build will contain this fix.

Tested it a little bit and have not seen any more crashes.