Self-casting "priority" working as intended?

Copy+paste from my earlier post in Report a Bug. Hoping for some responses here. I've noticed this a few times in games and have since actually done some testing on it. Even if you smart self-cast, if your cursor is hovering above a valid target, you'll cast the ability on that target instead of yourself. In most cases you won't notice it (for example, Kayle's ult/heal will still target herself since you can't heal or ult enemies, and in combat your cursor will more than likely be over an enemy or empty ground, however if your cursor is over an ally, they'll be healed/ulted instead). I've also noticed a lot of self-casts make your champ change directions (Kayles heal is the biggest offender of this). I'm sure a very slight "snare" (ie casting time, even for "instant" abilities) is intentional, sometimes the pathing changes entirely for about a quarter second or so, often times right into chasing enemies. I've noticed these for years but figured it was all intentional and that everyone knew about it and dealt with it. After my last game on Lissandra and I ulted Alistar instead of myself by accident, I learned my team had never heard of this phenomenon before, so I decided to write up this post on it.