One other signal is when the AI make odd connections that jump out. I was testing something out recently and the AI produced something that a person knowledgeable in field would never say. Something that someone just bull shitting me would say. I knew it was AI but it jumped out to the others I showed it to as well.
So true. AI definitely gives off the vibe of a very polished bullshitter. The kind of person who knows some jargon and knows how to gab, but doesn't actually know any substance and only repeats the popular phrases they've heard from other people.