Displacer Beast Bug? Or PEBCAK? - eviltoast

I recently got the ability to transform into a Displacer Beast at the start of Act 3. However, when I use the Illusory Copy abilities sometimes they just don’t take their turn? Like their turn comes up, they sit motionless, and then end their turn.

Is this a bug or a problem with how I’m summoning/using them?