Some Heimerdinger turret bugs
So a well known Heimer bug is his Q- H-28G evolution turrets will occasionally lock onto to enemy champions and shoot at them constantly even when they leave range. While these shots do not deal damage it is a bit of an issue when you know the location of an enemy 24/7 due to an ability bug. I don't know what causes this bug or how to recreate it but it has been an issue when it has tracked an enemy Evelynn.
The second bug is Heimers Q- H-28G Evolution turret will not aggro an inhibitor if you leave the turrets range, let it shut down, and then walk near it to reactivate it. The turret will attack enemy champions, minions, or pets (shaco box, yorick ghouls etc) as normal but cannot aggro the inhibitor.
Lastly Heimers Q H-28 Evolution turret will not aggro an enemy inhibitor after that turret aids in taking a tower. So if you place a Heimer Q between the tower and inhibitor and the tower falls the turret will not aggro the inhibitor but will target enemy champions, minions, and pets as normal.
One thing to note is a freshly placed Heimerdinger Q can and will attack inhibitors unless the above actions are done. These bugs aren't to major (minus the first one but it has been around for quite some time) but are a bit impactful if you are a Heimer player.