I'm not too well versed in this but it's most likely an issue with the pcb considering that the same issue happened twice. You should contact whoever you bought it from and address the issues and hopefully you'll get a replacement. You should also see if other people have had the same issue, so maybe hop into the monokei or hand engineering discords to see if other people have had similar issues.
The only other way I could see the pcbs malfunctioning is if you assembled it wrong, not likely but that may be a factor. Hope the issues get resolved.