I explained on IRC that the editboxes are handled by Windows, Windows is choosing (font-linking) the (what seems to be, lot of font are similar) MS gothic here, there's no issue with that.
if I paste the above chess clipboard into the editbox of a #channel whose font is Consolas or most other fonts, the editbox shows the symbols correctly. However when I press <enter> to display them in #channel, or draw them into a @picture, the icons are instead displayed with a poor replica, where the queen icon has a few low-resolution vertical spikes like Bart Simpson's haircut. Only when I change to a few fonts like MS Gothic do the symbols look like they do in the editbox, or when I paste those chess pieces into Notepad using Consolas.
In looking at /run charmap, it seems that the poor quality chess symbols exist in Fixedsys Excelsior 3.01, so mIRC is linking from that instead of getting them from where-ever Windows gets them from.
Consolas does not have the chess piece characters, simply. Whenever you're pasting into the channel, it looks like mIRC is telling Windows to do a font linking using the list of font
there whereas Windows by itself does it with a different list of font (not including this custom fixed excelsior, obviously).
Is it possible to edit the content/sequence of mIRC's own font-linking choices, or do I need to uninstall Excelsior 3.01 to stop that linking? Or if I do uninstall 3.01, is it going to use v2 or Excelsior NoLiga instead of Excelsior Regular? Excelsior are the only fonts that show the color control codes in the scripts editor using helpful symbols like [b] [c] [o].
Yeah if you're not happy with the glyph in the font, you should not use it, adding more font or editing the sequence wouldn't solve the problem, you would then find that the new order is causing others characters to be rendered in a way you don't like.