>>406881580
The issue is that when an expression has a unique iris it needs to switch places with the old one, and if the animation is slow enough you can actually see it. All of my animations are single frame. 

>>406881705
It's kind of hidden in the permutations tab, but I still can't believe I missed it, thanks. 
Would be nice if I could choose the duration for each expression but this is better than nothing.