So I completed the companions questline within the first 4 or 5 hours on my current character. I've gone on to do many other things. Currently I'm doing Boethia's quest, went back to Jorvaskr and who do I see sleeping? None other than Skjor himself! Weird bug.

You discovered his secret clone.

It's crazy. So much time has passed since his death. I'm currently 80 hours into my current game.

Just don't take any quests from him, I hear this might break things.

I can't believe they never fixed this bug...

does he still says "You need to prove yourself whelp"

In my game, yup. And it's kinda frustrating after a while, I just feel like yelling 'I'M YOUR HARBINGER, SHOW ME SOME RESPECT YOU IDIOT!'