BarDIMM Pro appears as loaded and licensed on the printer configuration page but barcodes are not printed.
When sending the BarDIMM Pro test files to the printer, barcodes are replaced with text characters and some very large black characters appear on some of the page.

Origin of the issue:
Printer firmware defect.

Ensure all your print jobs comply fully with the hp PCL/PJL standard by starting with the following sequence:

and ending with this sequence of bytes:

where <Esc> is ASCII code 27, hexadecimal 1B, and <LF> is ASCII code 10, hexadecimal 0A