GA R2D2 Smoke Screen Misfire?

I was battling a Bossk squad (Bossk, Boba, Greedo, Cad and Dengar) with my JTR resistance team in GA yesterday. I used smoke screen with R2 as the target - nobody got stealth, R2 made some noise and it was next character's turn. I don't see how this should have happened.
Am I missing something or is this a bug?