I came across this answer to “Adobe PDF for Ubuntu 64 bit 15.10” recently. The question is about installing Adobe Reader on recent Ubuntu releases. The answer explains the whole story with the different versions and flavours of Adobe Flash Player. Obviously that misses the point entirely and I flagged it as "not an answer". My flag was declined.
I know that we generally keep answer posts that attempt to provide an answer (unless they violate other rules like being link-only) and I agree with that. Though in this case I'd argue that, while the post tries to answer some question, it clearly doesn't try to answer or otherwise address the question that was asked.
Did I take the wrong measure to deal with this issue by flagging as NAA? What should I have done instead?
Or should we keep all answer posts that make an attempt to answer any question even if they go completely off track?
As an extreme case, someone going around and taking random answers from questions and posting them under random other questions wouldn't formally violate the rules (ignoring the fact about answer duplication which may or may not be problematic on its own depending on the circumstances).