Parking Brake Question

Did some work on my dive line parking brake about a year ago and it has worked very well until last week.

Last week it failed to engage the brake shoes even when the cable and actuator appeared to function properly. I inspected it and adjusted it today, but the problem remains. I tore it down, inspected it and found nothing that looked improper. Reassembled and adjusted per the FSM, and still the actuator arm/ cam fails to engage the shoes to the drum. Anyone know what I may be missing?