We already have a word for it? "Misfeature"
The opposite is the more interesting word though: hit bug. A bug/mistake/fuckup that turns out to improve the software.
A misfeature is specifically a feature that's just bad, while verschlimmbessern can happen with everything that nobody would call a feature (insert something about xkcd 1172). But yeah, it's pretty close
They're not bugs, they're undocumented features