I'm trying to do the last few challenges on my list as I've done all of them, but I've found that no matter what, the taunting one, streaking one and vehicle surfing and others won't update! And I KNOW I'm doing them all correctly.
I assume it's not the using cheats thing that disables stuff as I haven't used them and other challenges update fine, I just finished the blowing up Emos one and Boats Destroyed. I also and having the hijacking one fill up nicely.
So what could it be?