1. Tenebrous has a 1 second internal cooldown. - This makes increased proc chance of multiple tenebrous nearly useless, especially for fast attack champions
2. Tenebrous was NOT doubled like the rest of the enchants. This makes it really fall behind compared to just stacking radiant enchants with 2400 power now.
3. All Tenebrous enchants at all ranks state 8% after being slotted. This bug appears to be just in the text and not in the funtionality.
SUGGESTION: Either remove the cooldown or double damage from 8% to 16% for tenebrous to remain a viable option. Or both. If you're not going to remove the cooldown just remove the stacking proc chance because it's like you're tricking people into thinking running more than one is somehow beneficial, whereas with internal cooldown, it isn't.