In case anyone else has this issue I wanted to share:
TL;DR - If you v/oct jack doesn’t work, try the factory calibration reset procedure described in the manual.
I just installed a new Surface and everything appears to be working correctly except the v/oct jack wasn’t working at all! I carefully tested all the other knobs and jacks and the module seemed fine, so it was very odd this one jack wasn’t working. I worried it was a physical problem with the jack, like a weak solder point that disconnected while being bumped around during shipping. That seems unlikely though…
Before reaching out to support I carefully read through the manual to see if there was some sort of non-pitch-tracking mode it might be stuck in. And nope, there’s nothing like that, but … it occurred to me the module could theoretically be calibrated such that the v/oct input had a negligible effect. I wasn’t sure if I have accurate enough voltage sources to follow the full calibration procedure, so I just did the factory calibration reset described in the manual and now it’s working! Later I’ll carefully check that it’s tracking octaves well vs my other modules and perform the full calibration procedure if it seems out of tune, but it sounds good so far.
Anyway, I’m relieved nothing is physically wrong, but it’s odd it arrived in this state. I don’t think I accidentally re-calibrated it when installing it or performing initial tests. No big deal. I sorted it out relatively quickly.