Bug With Masking Tracking

I created a mask using the Pen tool. The mask's path was created to trace the outlines of a female subject who was being interviewed. The subject was framed in a medium close up shot. I was trying to use the Track selected mask forward procedure. I tried to engage the procedure three times. Unfortunately, each time I clicked the button to start the tracking, Premiere Beta crashed. I even tried to to engage Track selected mask forward 1 frame, but Premiere Beta still crashed.