Does anybody with a faulty X10 (stops hashing - blinking blue lights or not accessible, frequently - reboot sometimes working, sometimes not) has already replaced the Orange Pi? Does that help? Which Orange Pi did you choose exactly?
I had a few issues like you describe at first, but my issues were related to heat. I turned the fans down to 70 percent trying to "tune" it. Once I turned them back up to 100 they functioned without issue. Is it warm in the room that the machines sit? If they get even close to 40c they will start to malfunction in my experience.