Works differently than all other boon steals in the game, should work like all other steals obviously.
Differences:
Does not steal “stacks” of the boons; e.g. the enemy has 15 stacks of Might, your character is only going to receive 1 stack of might (unknown which individual might application/duration takes priority); if the enemy is using a boon that stacks duration, such as Protection, and has both a 3s and a 4s application of it (showing as 7 seconds total), your character will only steal the 3s or the 4s application of the boon (unknown which application/duration takes priority), not the full 7s. The target, however, WILL lose all stacks of that duration stacking boon, regardless of which specific stack your character receives.