LCDs are a bit broken- forgetting settings.
Steps to recreate:
1) place a group of LCD panels on a powered grid.
2) set them to 'text & images' ( group them all up )
3) change the background colour
4) now switch to spectator mode, and back to 1st person.
As if by magic, all of the panels are now blank- you must go back into the control panel and adjust the colour again before they all suddenly their settings. If however there is text written on one of the panels, that one will remember it settings, but all of the others will go blank when using spectator mode.