Thanks for the replies all.
Voltage switch is fine (120/60cycles) and IR cell red indicator flashing ONLY happens when head is plugged into A port, and modeling light on. This is regardless of power setting or strength of modeling light. Switch modeling light off on pack or head - flashing stops. Plug same head into either B port, modeling light on, any power settings on pack and no flashing. If it were a pack-level voltage setting issue it would be consistent across the ports.
All other pack functions seem normal, indicator works to indicate slow recycle, etc. The only issue with pack, so far, is the odd red flashing indicator. What is even odder is that it's not regular. One theory someone had is that IR cell was picking up off IR interference. Sounded off to me, but WTH. I tried it with modeling light covered (briefly of course) with bulb cover - no change. Tried in different room in case some bizarre interference or issue with power draw from my office - no change.
Best the CDN tech (1800km's away) could come up with was a pending issue with pack's A socket circuitry. With an out of warranty pack and nearest CDN repair depo 1800kms away and a couple of big shoots coming up in which I hoped to use the pack, it's a potential pending issue I don't need.
So, seller has agreed to take pack back -- is leaving later today. Sigh, now to find a replacement. So, if anyone's a Acute2 1200 (pack only) they want to sell, drop me a line. Aaargh.