It turns out this is just part of a bigger oversight on my part. I have some assembled SMT boards on their way back that are going straight into elec recycling because I used the symbol for the 2N3904 TO-92 and simply replaced the footprint with an SOT-23, having ASSUMEd the pin numbers would correspond. Ugh. Ugh ugh. I don’t know what else might be wrong in there but all the pick-and-place work is suspect.
Painful as that is, the price of writing off that work is peanuts compared to the time I would have spent tracking the problem down after getting everything wired up so I’m glad we had this discussion.
Going forward, I’m populating dedicated symbol and footprint libraries for JLC jobs. I’d already used a bit of Perl to implement the approach described here as a means of importing symbols for all the passives: Autogenerated kicad libraries for jlcpcb assembly.
If I can get this working at all I’ll probably be elated enough to start another thread to boast about it. Hope that’s OK. Thanks for the support and next time I’ll be sure to do more searching up front.