Class Req. doesn't work correctly, when armor is equiped via rightclick

[KiviTheFruit]

Serverversion: Spigot 1.3.2
Pluginversion: Permium 1.90

Bug: When a armor-item with the "Class Req."-Lore is equiped with a rightclick, while it's in the hotbar, it will sometimes equip to the player, even if he doesn't have the correct class. It works sometimes though.