Back when I was a union pipefitter/welder on several nuke plants, and was certified to weld any piping component on the site, we would see offsite vendor supplied piping systems show up. They were the worst looking welds, that we swore were done by some 1st month welder trainee. Some even had wire sticking out of them from MIG welding, others were full of porosity.
We would point it out to QC but it didn’t do any good. Eventually those were all tore out and replaced.
See my post # 39.