Heimer Turrets Get Confused at Structures

I've mentioned this before to no avail. I'll give you a scenario. Maybe if I break it down for you, you'll do your job better. I am Heimerdinger ( <-this guy). I have my turrets placed at the enemy inhibitor. They are attacking the inhib, as planned. A wave of minions appears. Expected. My turrets turn to attack the minions. Expected. The minions die. Expected. My turrets do NOT return to attacking the inhib. NOT expected. No. They just sit there, looking back and forth like mindless security cameras at an empty car park, while the enemy that just realized I'm taking their base returns to obliterate me. The turrets are supposed to continue attacking the inhib (or tower, or NEXUS!) after they are done with the minions. So. You wanna maybe get on this? Heim is my man and this specific scenario has decided more games than my entire team combined.