Multiple ForEver blocks cause EV3 to lock up- battery pull required

[julianrendell]

Describe the bug

Multiple forever blocks cause the EV3 brick to lock up. It can't be reset from the top buttons. Required battery to be removed to reset.

To Reproduce

Student's were looking to create a simple "camera" robot- two large motors under tank control to drive/turn, and a medium motor to slowly rotate a camera. Started trying a single forever block, but couldn't get simultaneous movement from three motors. Two tank motors would move the bot forward, and then the camera motor would turn a small amount. Tried two forever blocks, one for the tank motors, one for the camera motor. Appears to work in the simulator- tank motors and camera motor appear to be rotating at the same time, with different speeds.

Expected behavior
As per the simulator- tank'd motors move at their own speed, and simultaneously the third motor, in it's own forever block, all run.

Desktop (please complete the following information):

• Windows and Mac; EV3 with latest public firmware.