Heimerdinger turret issue

Played a game of Aram and had an ally on my team. For some odd reason his small turrets would continue to shoot even if an enemey was out of range. Then the ulted turret did the same thing.

I then played a game of Summoner's Rift afterwards and faced against an enemy whose turrets did the same exact phenomenon. I used 's ult and it then made one of his turrets stay stuck in mid air. It became untargetable and would keep on shooting while dealing no damage.