Corrupted Gem - herald of ice

I had Herald of Ice, added skills for the weapon, 2 weapon sets, added and removed dex str int, etc., and at some point, Herald of Ice stopped working and I got the message "Item cannot be used: - Not usable with current Weapon Set settings" even though I have the attributes, etc., and I change the weapons, and it doesn't work in any configuration. I made an identical gem, and the second gem works. So, with two identical Herald of Ice at level 9, the first one doesn't work, but the second one does. It somehow broke.