When I switch models in composer it seems to start forgetting how it can function within cursor and inconsistently makes changes to the file for me to accept vs put the suggested changes in a block within the chat or saying it updated it when no changes were actually applied to the file.
I have figured out that if I remind it that it is an ai model being used in the Cursor IDE composer function you can do xyz then it remembers for a little bit acts as expected and then forgets again. Playing around with the .cursorrules to see if that helps. Not a complete solution but helpful.