Headhunter Causing Enemy Animation Stall Bug

Certain bosses and creeps, particularly those not targetable during an animation period (Vaal constructs, Shark Boss when burrowed, Mud Worm Boss etc), completely stall while Headhunter has active Buffs.

Have confirmed, unequipping Headhunter to remove active buffs causes the stall to end (at cost of your buffs), so safe to say the interaction is with headhunter/its buffs.