I see what you mean. My eyes started to bleed after three seconds exposure with just the small part of the screen shot you showed. What would happen after exposure to a full screen of a colour scheme like that I hate to think! What colour scheme do you usually use?
Oh, as for the error, it looks like internal debugging that could be reported in a /msg to the gods using text copy and paste.
Nice of GrandFather to volunteer somebody else as the recipient. Too bad he doesn't have much of a clue on that point. But then, the majority of the cases I witness of "Oh, you should '/msg gods' about that" I quite disagree with. Luckily, most such suggestions don't end up being followed.
My preference would be to reproduce the effect using HTML, as was done with the original (not an off-site image nor just text). And I find '/msg' to usually be one of the worst choices possible for a bug report or inquiry (a compelling reason to keep the information more private being an obvious exception). After all, anybody who might have previously witnessed something similar might provide insights. And some future (or past) occurrence might even benefit from a search for other reports.
There is actually a group (with about 70 members, last I checked) that are supposed to be devoted to PerlMonks' code. Heck, GrandFather is even listed as a member of that group. But he seems not interested in looking at the source code, so perhaps he should just be removed from it.
And, no, I don't plan to dig into this bug at this point. Not even close to the top of my priority list.