In the chat window, after rejecting a suggested diff and trying to apply it again, or trying to apply another suggested diff, no actual changes are made.
Test:
In normal chat mode
Suggest some code changes, chat gives a code block
Press one of the apply options
Reject it
Try again to apply it
OR
Follow the first two steps after the first rejection and try to apply
Nothing happens to the code, though it is highlighted and it looks like cursor tries to do something.