I perused the varitarget circuit on the Playball schematic for a while and have to agree completely with MarkG. The only difference between the single circuits on the left and right side varitargets should involve the contacts and wires on the boards and wipers. It is probably caused by a sketchy solder point or a wire with a micro-crack inside the insulation.

Since you cannot duplicate the issue with the PF in the raised position, you might try moving around the R-side wiring bundle that goes back to the Jones plugs in the back right corner of the component board. Raising the PF may be causing the curves in the wiring bundle to change position and close a microcrack in the wire???.

Had a similar issue with the lights in a car trunk lid once where the flexing of the bundle was causing the rear running/brake lights to be intermittent.