Tahm w buggy

Sometimes instead of spitting out a minion or monster after devouring it, Tahm will simply drop it out of his mouth without any of the damage or AOE occurring. It happens enough for it to be annoying, maybe once in about fifteen devours. I cant quite figure out why it happens, but it happens mostly when the w reactivation is immediately after swallowing the minion or monster. Also, minions will sometimes become invincible at 1 hp for a couple seconds. Not sure if they are related, but i have only noticed this while playing Tahm.