I have noticed it on mine as well.. have 14K miles.. I keep mine on the HSI most of the time, just recently I have been switching to other screens and have noticed weird colors, like a red tint, on some of the other screens and some burn in effects. we will see if it worsens with time.
Humax 9200T by any chance? mine does the exact same thing, VFD was a poor choice for the MFD, i would have preferred they kept LCD, not convinced the VFD would even be that much cheaper...
VFD's are otherwise well proven and don't have nasty mercury back-lights to deal with (though LED back-lighting has come a long way and is becoming the norm in most other consumer devices). My observation isn't so much that this is burn-in, but rather the opposite where the more-often-used VFD cells are brighter than those that are used less frequently. This is especially obvious if you use the HSI screen 99% of the time, then scroll through to 1/5 min consumption or past trip records. Running reduced intensity (headlights on, interior light rheostat not on daytime mode) makes it more apparent.
Ohh Yes! Finally after 12,000K I can definetely see MFD burned in pretty bad I just noticed last night! More problems! Annoying. I am going to dealearship to see what they have to say. It seems it gets worse by time.