Had a problem, just very close to your issues. Pay a very close attention to the wiring loom that serve the displays,
Where in come in at the bottom of the display board and daisy chain the displays.
Have a very close look there and see if the wires are pitching or shorting that causing wacky displays issues
This issues sent me a wild  and nightmare chase, try everything from replacing the MPU and the display driver chips,
only end being wiring being shorted.

Hope this solve your problems and Good luck.