So I discovered something kinda awful. If you’re using Shago and you use the Ultimate, it doesn’t finish off the Bastion (can only be killed with an Ultra) enemy. Instead, it just locks your controls and lets you get beaten to death. Not even losing a life bar will wake you back up.
I can foresee this being a big issue if/when other Ultimates are added to the game.
When they say beat it with an ultra, THEY MEAN beat it with an ultra! 
On a serious note, this is a huge bug that should be fixed.
Shago’s ultimate works better when stacked with Zarya’s or Mei’s. That’s probably why the Bastion survived.
Well…it does say “can only win with an ultra.” Not an ultimate. So it kinda does make sense. The freezing part however…not so much.