Monarch 9855 Application Notes page 23

If an RFID error occurs, an overstrike pattern is printed on the label
without any data.
If a non-RFID error (verifier error) occurs, the data prints on the label
with the overstrike pattern.
RFID Overstrike
Non- RFID Overstrike
printed from a verifier
error
Setting Up the Printer 3-5