This ^LH comes after the first field, where it is documented as having no effect. The home position you intended is not applied.
Put ^LH immediately after ^XA.
^XA^FO50,50^FDX^FS^LH30,30^XZ
^LH appearing after the first ^FS in the format.
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 ^LH comes after the first field, where it is documented as having no effect. The home position you intended is not applied.
Put ^LH immediately after ^XA.