If this holds true ...
at lvl 80, I never get any drop from bossess like MPE or Diaper.
Only Thunder King give drops...
I'm quite sure cause I stock up some tag fur at about lvl 70,
I was hanging out @ Dead Mine and slay MPE a few times and ALWAYS get some drop from MPE.
Later at lvl 80, I NEVER get any drop from MPE.
If you want to test it, try bringing your friend who's about lvl 50-60 and slay MPE.
I can guarantee he'll get his share of boss drop (party drop of course) while you get nothing.
Anyone up for camping boss spawns?