I think that yaw can occur in that situation. First there might not have been enough right peddle to counteract yaw without the help of ground friction and when the lever comes up you lose ground friction, so around you go.
Also, if the lever came up the thrust / drag on the blades increases and the governor reacts to maintain RRPM by adding torque, so surely the rise of the collective would increase torque. Or am I missing something here?