For both of these scenarios, it seems to happen when the context limit is getting full and the context is summarized. I've found it usually works to respond with the right file, i.e. "great, let's apply those changes in @path/to/file", but it may also be a good time to return to an earlier conversation point by editing one of your previous messages. You might edit the message that got you the response with changes not linked to a specific file, including the file path in that prompt will usually get you back on track.