I'm still pretty early in my game (13th level), but this helmet makes my Thorn Hunters and Thorn Warriors easily my most damaging units. My stack of about 700 Thorn Warriors hit for about 2000-3000 damage on non critical hits. I'll probably phase them out sometime later, but for now they are doing just fine for me!

In your variant this item really seems to be useful, sorry that we can't help you with this bug.

Have same problem with crown of elves, surpressed it few times, still nothing happens, ver 1.7 Altough its great item i found prismatic helm 1 hour later :D so it isnt much loss but still looks like a bug

I have also started to see this behavior. The jackboots and Elven crown especially is where I first noticed it but it's starting to spread to other items. Today that dwarven chest that gives +30% to attack and def is busted.

I am on v1.7 also...just wanted to report so the devs knew it was really a problem. Oh prior to 1.7 things were fine.