I don't know if this is already implemented but I got hit quite a few times right after an ultimate finished casting. For some it's alright since you can move during the ultimate, but for Titania for example it seems unfair.
#Invincibility frames after ultimate use
spiral wave
simple moth
you should have full invuln for the entire duration your model is changed and then a few frames after
if something in particular is hitting you it's a problem with the specific thing tht's hitting you
buoyant ermine
There have been several instances in the game where I've gotten out of the Ult transform and have been locked in place by the animation long enough to be hit by something. 100% agree the invuln time post Ult needs to be longer.
humble hearth
I get hit coming out of Ultimates all the time. if it's specific attacks that are hitting after Ultimates, it is a LOT of them