bit of a funny one but the emote just stays on and never disappears, it makes me look like a troll 
while it does disappear when you use the emote again, it does come back at random points
#The emote stays on forever
delicate frost
lusty shard
bit of a funny one but the emote just stays on and never disappears, it makes me...
I was able to reproduce this, seems like this happens when you emote the moment you are about to get KO, when.you come back, the emote stays forever unless you emote again or the game ended
delicate frost
the weird situation is that i didn't get kod :C
lusty shard
wah really, I am unsure though, but in my case it always be like that so I emote before getting KO just for fun
delicate frost
gentle olive
That is indeed the most common way this bug occurs, since it can happen on all strikers, but there are also some other triggers.
On Rune, like you're playing in the clip, it can happen when you use your secondary while emoting. Hope that clears things up 
sleek sedge
Has happened to me A LOT. I think it happens when you emote right before you die sometimes. It goes away easily by pressing any emote again, but I usually purposely keep it up for the lulz and to distract the enemy team.