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It would not be possible for just one SMD resistor to be the wrong value, they come in bulk packaging where every unit is identical from the factory.

https://www.google.com/search?q=smd+resistor+tape&client=fir...

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Not if it's on tape & reel with automatic P&P, I agree. But if those boards are made in such small quantities that they're being hand-stuffed, I wouldn't be surprised to see an errant resistor somewhere. Maybe the human pick&place was distracted and picked from the wrong reel, or 100 resistors were dumped into a bulk tray and there was a 400ohm resistor on the bottom of that tray or any number of scenarios.

I've seen so many assembly errors in my time that I'm pretty sure it was something like this that happened.

Or PnP machine didn't place the resistor or misplaced the resistor because coordinates were wrong in PnP program, it was found by AOI machine, and then wrong resistor could be placed by rework technician.

Who knows what happened at that factory, maybe someone made a mistake. The part might also just have failed.

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