Printer, white lines and square braquets

to bring some more light to this issue…
I have two bematech printers, one mp-2500th and a mp-4200 th
both are the same… apparently, jajajajajjaja

mp-2500th works great, no white lines, no square braquets
mo-4200th works great, YES white lines, YES square braquets…

strange, on version 4.1.17 mp-4200 th did not print the square braquets.

Hope this helps a little bit more to catch the bug, jajajajajjajaja