Indefinitely stealthed Twitch

I don't know how to reproduce it, but I just played a game where I somehow managed to either become stealthed for far longer than Ambush should allow (The screen wasn't darkened during this "stealth") or where the character model is translucent so as to indicate stealth without actually being stealthed. I don't know which because I managed to resolve the issue by just activating Ambush again before anyone on the enemy team could see me in theory anyway. I did, however, farm minions during this state and it still did not take me out of stealth.