Bug with Self Casted abilities. [GAMEPLAY]

Since a couple patches ago I have noticed a bug that gets me killed very often. I have self cast bound to ALT and if i hold it while casting for example E with karma it should target myself. This is how it have worked for as long as i remember. But since a couple of patches ago ive noticed that if I hold self cast then happend to have my mouse on an allied champ they spell will cast on them. Is this intentionall or not? And if it is. Why? Its so bad since i cant keep track if im holding my mouse over an allied champ or just random terrain. If I hold my self cast key I want the spell to be cast on me regardless of what champ my mouse is hovering, thats like the whole point of the key bind...