It never occurred to me that it might be a filter for bad language. Is that a thing? I'm skeptical. I think you're right that it's just a bug. Don't know if it's Connect or Lemmy that has the bug though.
I thought it was just a “you can’t call that dude a cunt” feature that subs can opt in our out of and they were just making sure I wasn’t offending anyone.
Certain instances, such as Lemmy.ml, uses a filter that censors swear words but that's different from this issue. My other comment in the thread explains the issue.