Not exactly life-critical but on games I play I've asked for optimization advice and it has responded with info I know is 100% wrong. I end up replying with URLs to the info and pasting the direct info from it. The AI of course goes, "Of course!".
At work I constantly get commands that dont work in my version of some app or OS even after I told it the exact version I'm using. I'll even post the response from tech support and it'll throw up its virtual hands and say "of course!".
I've also noticed that AI has now been around long enough to start posting clearly outdated information.