It certainly isn’t broken on PC/mobile. I’ve had it trigger repeatedly in the last couple of days. However, your hero has to be at the front of your team for the trait to work. Same with the Archer class, too.
Same applies to troops like wrath…it only explodes 2 yellow gems with a skull match if its wrath itself that inflicts the skull damage. Wrath or hero must be top troop (not necessarily in p1 cos you may have lost the troops above it) for the perk/trait to fire.