My follower doesn't accept equipment at his own level if my character's level is lower.
I have a new character at level 6, and my follower is level 7. If I try to put a level 7 armour on him, he refuses. It doesn't give the usual doh sound, and say that his level is too low. It just jumps back in my inventory (like if I try to wear it myself). I can give him a level 3 armour without problem, but not a level 7 one.
I know that it is a very rare condition to be lower level than ones follower. I just thought I would mention it, as it does seem to be a bug.