Does the USB cable you’re using incorporate a drain? If the keyboard case isn’t grounded and static buildup isn’t being properly discharged, that could cause the issue you’re referring to.
Try swapping cables and PCBs if you can to isolate the cause.
Yeah, I'm on my fourth USB cable, including the LZ one included with the board. Issue seems to happen with all of them, perhaps worse with one of them than the others. Tough to say with an intermittent issue.
I have another build based on a second PCB and plate. May swap that over if the paper and electrical tape don't work. Honestly, though, I really want this build to work properly. Ugh.