Where to Find SKULLS - Conan Exiles Patch Day May 11, 2017 

Ive had that inventory bug before the patch a few times you can put the items on your hotbar and than drop it or restarting the game fixed it for me

THE MAP

Thats not a bug, you need to change your inventory organisation thing at the top from by type to by custom

I'm having problems getting the skull of yog. I've been pick axing all the dead bodies I come across but I don't get any.

If you want skulls, just farm unnamed city for a couple hours.