I loaded my save file and I'm wearing the Jagged Crown atop Krosis... and my head is gone. I have a body but no heading... and I'm wearing a crown.
I think it's a glitch. Put on Krosis first and then the Jagged Crown and you are able to wear both BUT it actually decreases your armour rating which is weird considering it says the crown adds 40.
I had 615 armour rating complete with Krosis so the Jagged Crown should have boosted it to 655... but I went down to 524 so it actually detracted 91. Another weird thing is that it says the crown's armour rating is 40 when you are not wearing it, but when you have it equipped it says that its armour rating is 32.
So, yes, I think it's glitched.