I get a bug as well, but it’s far more dramatic, my whole character and all the exposed transforms all fly off in different directions… It completely breaks my game. I’m still looking into if there’s a workaround but if i can’t find one I’ll also submit a bug.
Edit -
I’ve discovered that my bug only occurs when i have Rig Optimize Game Objects enabled and run on iOS. Optimised on PC or unoptimised on iOS both work as normal. I’ll submit a bug for this.
I submitted a bug report about this (761908). The “Optimize Game Objects” option seems to be almost completely broken on iOS right now. I’m pretty sure it’s a new bug in Unity 5.3.