Tahm Kench's Devour

I've encountered a bug that appears when you use Tahm Kench's W. When you devour and ally, minion or neutral monster sometimes the cooldown time starts before you spit them out; making you unable to spit out said ally or minion until it naturally spits out on its own and then the cooldown is restarted again. Its most annoying when I try and devour a minion for a quick harass and I cant spit him out.