This is a bug fix I am happy about. :)

kill a boss a second time and hang up the trophy on an item mount

Never mounted a boss head anywhere? Or hung out where they are? They're quite chatty.

Ok then.. i kill them and hang them at the stone circle.. never looked back TBH. Never tried to re-kill them either :/

I mounted the first two heads on the wall of my trophy room, but they wouldn't shut up so I stuck them in a chest.

Yeah mine wont shut up either.
She's always talking about who said what, and what her friends were wearing and what happened at work etc.
Very annoying.

Re-killing the bosses are good so you can hang their heads at your base though.

"So you were my death? You look small and soft... Tell Odin he may have broken this form but the wilderness will never submit to his rules..."

-Eikthyr's mounted head

Y'know the trophies hung at the middle circle talk aswell? My base is very close and built up around the circle so I run through and stand near them a lot and have had the odd whinge from the trophies