An assortment of possibilities exist:
1. The gripper assembly needs to be lubricated. Although the release action is motor driven (the gripping action is spring tension), it may be binding just at the point of release where the cam switch will change the circuit from transfer to scan.

2. A faulty cam switch is either losing connection or not making connection when necessary.

3. The gripper arm is binding against the magazine, thereby shaking it will allow it to travel to full extension and release the record.

I hope this helps a little. I will see if I have any manuals that give the sequence of operation that might help you solve your problem.

Respectfully,

David