Sometimes when ulting with lux laser it will not deal damage. i was using the star guardian lux skin so maybe it is the skin that is bugged but it happened 2 times in my last game... the laser was what looked to be very accurate and just caused no damage.
I suspect this is another case of Riots alleged 'hitboxes'. I forget exactly what the reasoning was, but it had to do with the way that the game draws the Lux beam compared to it's actual in game position. Because it's elevated off the ground or something.
Sometimes it will look like it should hit but doesn't, sometimes it will look like it clearly missed but get you a kill.
Were you displaced during your ultimate?
When Lux is moved while channeling her ultimate, the animation of the ultimate separates from its actual hit-box. If they were in the laser animation, they wouldn't actually be hit by the ultimate while another location was.
