Sejuani permafrost bug

Consistently (at least once every couple of games) when Sejuani casts her "E" on something with full stacks, the spell just... doesn't work. The stacks disappear, the ability goes on cooldown, there's no damage and no stun and no lockout period for more stacks to occur, they just start back over at 1. It seems to be linked to enemies being displaced or having their movement otherwise affected somehow. LUCKILY, so far--knock on wood--I've only had this occur vs an enemy CHAMPION rarely, and never in a situation that didn't end up resulting in a kill either way, but I've had it happen against jungle minions, ESPECIALLY rift scuttler, near constantly, so I wanted to make sure that someone at Riot was aware of it.

I've uploaded a video of it happening a COMICALLY large amount of times consecutively