I haven't seen a lich rumor boss since i was lvl 17, i thought they were removed from the tavern rumors. Now i'm lvl 23 and i finally got a lich boss but can't find it because it is in unknown location. I don't know if it's a bug.
"Unknown area" typically means you heard the rumor about the Lich, just not where it is yet. You need to listen to more rumors to learn more details about where the Lich is hiding --or-- since Lich's tend to appear in crypts so you could just start clearing out Crypts.
The "Unknown area" glitch is related and a known glitch but doesn't seem to be the case here.
MOD NOTE: moved thread to General as it really deals with a general question about Rumor Bosses rather than Feedback.
David I may have run across this, although it is possible I was playing an outdated version of the game at the time. My recollection was that it was the Nilorth cave spawn that was bugged... Worth checking though.