It sounds like you need a Print Driver update for the Brother printer.
Filemaker gets its printer magins from the Print Driver [page setup]
Your Layout Printable items determine how the printer gets the printable objects on that page that may be RESTORED [from previous use] by the Print script.
Also, your zebra printer is likely printing from a custom page size. Check printer setup before printing to see if that custom page size is still selected.
(And if your file is hosted over a network, sometimes you have to pull the file down off the network before fiddling with printer settings in order for the "default" settings to persist.)