UPDATE: I swapped out the BCR for a fully charged green battery and now my Zephyr runs as intended. It cycles normally; Neutral-Forward-Neutral-Reverse. And, now when I reduce the throttle to zero, the engine sounds persist for a while and simulate a gradual shut-down.
So yes, it appears that I have either a faulty BCR or a faulty PS1 system preventing the BCR from charging. Not sure what I will do, going forward. For now I guess I'll run with the green battery.