Talon Assassin's path bug on red side

So I was playing in a ranked game, and i was running from base back to lane, and i used his E, Assassins Path, on one of the nexus turrets and it didn't get an indicator that it was on cd. I used his E on it again and i jumped over it again, but it got the cd after the second time. I waited till I could jump over it again the same way by running from base and jumping from behind it, it didn't get the cd. Then i jumped over it a different way and it went on cd. I kept jumping from behind it from recalling afterwards and it didn't get any cd, but if i jumped any other way it went on cd. Just a minor bug i found.