Teemo ult bug {{champion:17}} Patch 5.4

When playing with teemo recently i noticed when i placed a mushroom right as the timer for another one should've registered and added a new mushroom, it didn't add a new mushroom and i had to wait another 23 seconds to place one. Example: Have 2 mushrooms, timer for the third one has 5 seconds left. Place 2nd mushroom right as timer ended and should've given me another mushroom, it didn't. Had 1 mushroom after that, not 2 like should've.