To not directly ground Pin 1 to the chassis is, indeed, a common "mistake", one I have made myself during my DIY efforts. In my case there were apparently no adverse consequences.
As for my VTV copy, the XLR connectors are grounded -- I can't speak for other peoples' copies.
What I agree with, however, is that even a single shoddy copy can have negative consequences for a maker; makers need to take heed of this and apply adequate QA.
Glad to hear you got a good one! I think the random sloppy drill holes on mine were because the DIY case supplier VTV uses (Ghent Audio) didn’t at the time make pre-drilled holes for the Hypex NC1200 (they do now, though). Of course it was very sloppy work as a matter of fact, and we should expect better at this price given how easy it is to do right (hopefully me stating this fact doesn’t revive a flame war again), but if the issues stopped at the drill holes cosmetic issue alone, I probably would have kept them. (But of course, the issues didn’t stop there.)
If I were you I would open it up and make sure the ground and AC mains power lines are all wired correctly, if only for peace of mind. The most worrying thing to me about my units was the grounding and loose connector issues (on top of physically missing screws just hinting at a very low degree of attention to detail during construction, thus casting doubts on its safety and reliability in other ways).
For example, the frayed pin 1 connector was worrying since the frayed wire strand comes uncomfortably close to the other signal pins. Note that these XLR sockets are very loose so that whenever you plug the XLR cable in and out, they wobble around quite a bit. Ordinarily this probably isn’t a big problem, except for when we consider the exposed frayed ground line there sticking out to the side towards the other pin lines (with no shrink tubing or other insulation to prevent this).
If you’re willing to open it up and do QA and manual repairs as necessary, then of course VTV can work. Personally I think they’d be far better off if they just shipped amp kits and leave the assembly up to the customer. When a product is delivered as a complete assembled product, the customer should not be required to open it up and do QA and repairs themselves. And if the customer has this technical expertise already to validate a sloppy construction job (which we know for sure happens for some percentage of their units), it would be better if VTV just shipped them as kits so that there is no mismatch of expectations about the quality of assembly. IMO.