It looks like the passive “splintered dominion” gets snapshotted.
If you pick the node, summon the mages then specc out of the node while having the mages summoned, they will keep the chance to cast additional projectiles.
Had that node picked (1 point) then removed it to get different nodes, but saw that the mages were still casting 3 projectiles sometimes. Guessing that the 25% chance/per point persists as long as you have them active.
No clue if anyone has posted this before couldn’t find anything.
Thank you.