With the newest Zebra printer, and even on the older ones, I’ve ran into this twice. What was happening is that the client was pulling up hard on the tags to tear off and pulling the alignment off each time. So we could dump it OK and geta green light, but after printing the first set of tags it was acting up. That notch in the hang tags just barely lines up over the sensor, and pulling tags the wrong way was just enough to throw it off. Just FYI, somethign to watch for.