Risers that fail - down to faulty USB cables?

I bought a load of risers (50+) from the same source I'd bought from before (via Amazon), but the latest batch seem to end up with one or more risers on each rig shutting off (0 h/s) after a few hours.

It looks like the USB cables are poor quality and getting the whole lot replaced by the seller is proving problematic.

Has anyone had similar problems where the USB riser cables are poor quality and if so, did you replace the cable with a standard USB cable? Or does anyone know if a standard USB cable will work?

Yes, I've had this. Replaced all of mine with 3rd-party USB3 cables. Solved some issues, others remain. When you use cards that pull a fair amount of power from PCIE, they heat up. My guess is that as they lack cooling solutions, the risers themselves don't cope well with high ambient temps and flake out. I've noticed this happening with my GTX 1070s in the afternoons / early evenings when the ambient temp of my garage is highest. They also die more often when dual-mining ETH vs ZEC. This does not happen with my GTX 1060 rigs. It's strange, though, as the GPUs run cool at below 65c.