This label changes a printer setting that outlives the job. On a shared printer the next person's labels come out different, and nobody connects the two.
Move printer configuration into a provisioning job that runs once, not into the label format.
^XA^MD30^FO50,50^A0N,30,30^FDLABEL^FS^XZ
Any persistent printer-configuration command inside a per-label format: ^MD, ~SD, ^MT, ^MM, ^MN, ^SS, ^PR or ^JUS.
Neither ^PW nor ^LL is set. Both fall back to a value stored in the individual printer, not to a value in the spec — so the same ZPL prints differently on two printers of the same model.
Set ^PW and ^LL explicitly in every format.
This label changes a printer setting that outlives the job. On a shared printer the next person's labels come out different, and nobody connects the two.
Move printer configuration into a provisioning job that runs once, not into the label format.