6. There have been issues where a pick & place robot assembler was loaded with the wrong value of a pull-up resistor. The wrong resistor didn't kill the circuit; was marginal and made some boards flakey. This is from personal experience at a company where I worked.
7. If the pick & place machine runs out of a component such as a bypass capacitor, that circuit board will be short one part. If the part is "non-critical" the board will work, but not properly.
8. All new circuit boards use surface mount components as opposed to the old through hole components. If a though hole was misaligned, the component would miss the holes and smash into the board, easy to see. If a surface mount component is misaligned, usually it doesn't matter since the component will actually float on the melted solder and align properly. Except when the temperature of the soldering oven it too low and the solder doesn't properly melt and is only heated to a "plastic condition". In addition there could be a cold solder joint. Cold solder connections usually only show up weeks or months later after the connection has oxidized.
in other words.. your manufacturing crap.. and expect sw to work on every unit the same.. and also ask for premium $$
no seriously speaking loading wrong wheel might happen but not planting a component cause if the tape ended its auto detected and stops also is auto photo checked since 10 or so years.. same with planting, the alignment is photo checked.. and precision under 0.1mm also these machine plant some 250k/h and more and not one component but mostly all of them on same machine
regarding the producer not knowing.. seriously i mean seriously..
regarding they dont give a crap.. FOR SURE
Don't give the circuit board manufacturing too much credit. The far east manufacturing industries run hot and cold, mostly due to smart phones; high volumes for a while and then it ends until the next version.
While vision systems are in place; small volumes like routers, NAS boxes, switches mice and other low tech stuff (a router is low tech) are likely to be built with equipment removed from the most advanced manufacturing plants.
Someone somewhere suggested (I believe it was Chadster on the Linksys board) that there are millions of these in the market place. With all of the various routers currently available that would set world wide router sales at 50,000,000 plus a year. I would think that is crap.
I could get my mind around 100,000,000 plus modem routers bought by ISP's world wide; I just can't get my mind around a router to sit behind a router in huge numbers when 99.99 percent of Internet connections use what the ISP installs.