I've received a few in-game tells asking why I have an off-hand on my Zealot with the Spike proc (2% change to deal damage back to an attacker) as it can break detaunts, which is not good for a healer.
The answer: because it doesn't break detaunts.
I tested this a while ago and I've tested it again today and it does not break detaunts. Here's a screenshot showing the detaunt still being applied after Spike X has triggered. I've cut and pasted the enemy unit frame just so you don't have to look at my entire UI. If you've held off on using a 3% crit Fortress weapon due to worrying about the Spike proc then worry no more.
That is all.