Lux and Ezreal ULT Bug

So, for the past few weeks as I've picked up Lux again I've noticed an interesting (to say the least) ultimate bug that happens about once every game or so. The bug happens with smart-casting (which, I use) and aiming your ult. If, let's say, the enemies are in dragon pit, Lux aims her lazor at said enemies and presses R, there is a chance that the ultimate will fire backwards. There have been about 5~ games I've played with Lux where this occurs. My mouse is pointed AT the enemies and the ultimate will still fly backwards. This has even happened today in a game I played (luckily the ult wasn't game-breaking for my team). Also, apparently this bug happens with Ezreal's ultimate too. I was in a game with some friends over our teamspeak client and he was playing Ezreal. He shot his ult towards the enemies and it flew backwards causing him to miss our enemy Sona, proceeding in him dying. Over our teamspeak we could hear him confused as to why his ultimate went backwards. I don't know if this bug is "game-breaking" per say, but it is very inconvenient to say the least. Hopefully this gets addressed! Sorry for not having a picture, I don't have a recording device nor do I know when the bug will happen.