That's interesting, I can see two causes, first the blade stop hole being too small, or the thumb studs too big, so then it's a matter of them changing their dies more frequently to keep higher tolerances in the interface, or even just chamfering the hole in the blade slightly might eliminate most of it. It's possible they could use a softer material for the blade stops but on a flipper that's probably a bad idea. That simply comes down to the cost of that being more or less than the number of returns they get. Second would be impact over time of the blade stops, but it sounds like people are seeing this mostly on knives out of the box so it's not that, and even on those that notice it after use it may have been a tiny fracture to start and use simply made it worse.
There's lots of high tech methods to detect cracks, dyes, xray, spectral etc. but those are usually used when their is a concern about fractures you can't see in high end applications. Plus lets face it, most of these companies are not putting enough QC into their knives to catch blades off center, really bad grind lines, burnt tips, visibly cracked blades at the thumb studs, etc. There's no way they are going to pay the $ to do more costly fracture testing at a high sample rate.
It's also interesting it's the 3rd most frequent reason a dealer returns knives before they get into customers hands.
That said any of the reputable companies are going to make something like that right, so it wouldn't influence my purchase decision.
