Post

those were bare PCBs and we get 8 assembled ones, so it's not an issue for the project, it's just cursed

I have had PCBs with S/N's in the 30's for an order of 10, from which I deduce that they have a lot of production failures for low prototype runs and just toss whatever is surplus. Perhaps you had a bad roll of the dice, or they broke them during assembly. "Lost" might very well be a euphemism.

they had a bunch of holiday days recently- maybe the shutdown led to some pipeline chaos?