Leveling up breaks "stand" command [GAMEPLAY]

Basically, if you hit "S" and your character stands still, he/she isn't supposed to auto attack any enemies at all, be them champions, minions, or monsters. However, if you level up an ability using the hotkeys (haven't tested via just clicking an ability level-up), your character will auto attack something without any command. This is especially annoying when I'm playing sona support, as I try to save her passive proc for enemy champions.

To reproduce, simply head into a lane and hit S. When it's time to level up, be sure there is a minion in auto attack range and use the hotkeys (in my case its CTRL + ability (QWER)). He/she will break "stand" command and auto attack the nearest target 100% of the time. No videos or screenshots, but it's literally 100% guaranteed.