If you use a buff such as Visions of Power or Sorcerer's Veil, that has a long recast time, the spell gem is supposed to remain grayed out until the buff can be used again. But, if that toon casts a clicky item, the spell gem will un-gray itself. The spell is not usable again and if you click it you will get a message that says "Spell Recast time not met yet."
Client: SoD