I'm not sure how your setup or your stressing is relevant here. I've got 3 devices, 2 of which have zero issues. Clearly, if it was a problem with my setup then all 3 would exhibit this problem. I've tried this device on 2 PC's. One is a Corsair One Pro and a mining rig with a BioStar TB250-BTC+ motherboard. The problem exists whether I'm using a USB 3.0 port directly from the motherboard or via a powered USB hub. If you're suggesting the problem is any one of these USB ports then the other devices would surely fail, which they don't.

When this issue happens, the other 2 devices happily "just runs and runs and runs and runs". This device has a much higher error rate and much lower share rate than the other two and then just completely dies.

What's interesting is that while adjusting the pots, I've had the inductor fail to get a voltage reading and I've had to unplug and replug the device in order to get a reading.

So the plot thickens (well not really... I think I just have a bad device).

These devices shipped with the following voltages Core: 0.714VDC  Mem: 0.771VDC. I changed them to their supposed defaults listed in the first post and was able to get it to Core: 0.751  Mem: 0.854. Now the error rate is consistent with the other 2 devices, except I constantly get these errors after a few hours:

[2018-02-03 10:45:24] FutureBit Write error: Permission denied
[2018-02-03 10:45:24] MLD 1: ASIC has stopped hashing, attempting to restart
[2018-02-03 10:45:24] FutureBit Write error: Permission denied

I've dropped the frequency from 756 (where the others are running happily) to 600 and all steps in between. I've been troubleshooting this for days and keep ending with the same result no matter which USB port or hub I use. I've run this thing solo, with the other two, basically every combination I've tried gets these errors.

Not sure what else to try at this point.

Yes, it is for sure affecting the hashrate and, as expected, the accepted shares are much lower on the one MLD (similar percentage drop). Even when running standalone on the same USB port as the other device I see 5-10% error rate and a much lower hashrate. I'll try to adjust the pots and will check them first with the multimeter to see if they are even the same.

I'm using one of the recommended powered USB hubs from Amazon which puts out 1.5A per port.

I ordered 2 Moonlander 2 and have them hashing. The problem is that no matter what I do one of the sticks have an error rate of 5-10%. I've tried modifying clock settings, different USB ports, different computers, powered USB hubs, etc.

One stick is <.5% error rate and the other is 5-10% consistently. I've gone as low at 600MHz and as high as 796 each with similar results.

I've purchased directly from the developer on eBay. Not sure if I have a defective unit or I need to tweak the pots maybe?

Interested to hear any ideas on how to troubleshoot this.