Claude loves to delete comments. I setup specific instructions telling it not to, and yet it regularly tries to delete comments that often have nothing to do with the code we're working on.

It's so hit and miss in Rust too. When I ask it for help with a bug it usually tries a few things then tries to just delete or comment out the buggy code. Another thing it does is to replace the buggy code with a manual return statement with a comment saying "Returning a manual response for now". It'll then do a cargo build, proclaim that there are no errors and call it a day. If you don't check what it's doing it would appear it has fixed the bug.

When I give it very specific instructions for implementation it regularly adds static code with comments like "this is where the functionality for X will be implemented. We'll use X for now". It does a cargo build then announces all of its achievements with a bunch of emojis despite having not implemented any of the logic that I asked it to.