Unison CMEd Corrupted Display

As rebooting sorted it, then it's probably nothing to be worried about.

These kinds of weird glyphs can turn up if the internal communication between the processor and the LCD display card gets interrupted or corrupted momentarily, putting the two 'out of sync' - once that has happened, the LCD needs resetting to get in back 'in sync' with the processor.
This has no effect on the rest of the system - it's purely the LCD itself getting confused.

If it recurs, then it's worth looking further into it - it's most likely to be dust and detritus affecting the communication between LCD module and the internal processors.

If you didn't already, it's probably worth opening up the CMEd and cleaning any dust or other detritus out - stuff does tend to collect in them after many years of being ignored!

I did have a customer, who had a cracked LCD on his CMd and it did prevent the dimming engine from booting up.  Once it was replaced, all was good

For reasons I'll never understand, the dimmer rack was mounted on a wall about 8" above the floor.  Then they made the room a weight room,  and a bar-bell hit the dimmer.

Did you ever try to config a rack mounted 8" above a nasty ex-factory/ now-a-strip-club basement floor?  You can't see the LCD with out laying on the floor!  This is a basment floor one does not really want to be laying on...but we wont go there, except to say, be aware that a faulty LCD can kill the dimmer, so make sure it isn't a hardware fault you are seeing.

I did have a customer, who had a cracked LCD on his CMd and it did prevent the dimming engine from booting up.  Once it was replaced, all was good

For reasons I'll never understand, the dimmer rack was mounted on a wall about 8" above the floor.  Then they made the room a weight room,  and a bar-bell hit the dimmer.

Did you ever try to config a rack mounted 8" above a nasty ex-factory/ now-a-strip-club basement floor?  You can't see the LCD with out laying on the floor!  This is a basment floor one does not really want to be laying on...but we wont go there, except to say, be aware that a faulty LCD can kill the dimmer, so make sure it isn't a hardware fault you are seeing.