Priest's Guiding Light bug?
The priest's description says the Guiding Light debuff can also be triggered by allies, wands, and some artifacts but I haven't seen any wands or allies triggering the debuff on mobs. Is this a bug?
Triggers means it "sets off" and removes the debuff, thus causing the extra damage. It doesn't apply the debuff. This definitely confused me at first, too.
I don't know what artifacts it means. Maybe the Master Thief's Armband?
Ah, I see.
In that case, maybe having that part as a separate sentence and saying hits from allies, wands, and artifacts can benefit/take advantage of the spell may make it less confusing.
I think you're on the right track. I think separating the sentences would make it more clear. And not using the word "trigger" since it's ambiguous.
Here's one attempt at clarifying it.
The Priest can cast Guiding Light for free once every 100 turns. Allies, wands, and some artifacts will now remove the Illumination debuff while causing bonus damage equal to their level.