I experienced twice a bug when selecting text in a channel window, the problematic lines are of the format:

&#9940; &#128338; [18:04:55] &#9733;@nickname <message>

I use the font Tahoma, which does not have this black star character, from this thread, it looks like the font used for my system would be ms sans serif.
In some cases that character can appear using two differents glyphes.
On a clean install of mIRC 7.49, with /font > Tahoma > 16, using this:
Code:
ascii return $regsubex($1-,/(*UTF8)(.)/sg,$asc(\1) $asc($mid(\1,2)) $+ $chr(32))
nfill {
  var %n $iif($1,$1,1)
  while (%n) {
    var %r $regsubex($str(a,10),/a/g,$iif($r(0,1),$chr(3) $+ 07 $+ $iif($r(0,1),$chr(32)),$chr($r(1,65535))) $+ $iif($r(0,1),$chr(9733),$chr(15)))
    echo -a $ascii(%r) -- %r
    dec %n
  }
}
in alias, you can see in the following video it is easy to get both.
It is not clear how but usually, when I start a clean 7.49, I'll get only one version of the glyph (usually small), and using /nfill, it will always change either all of them or some of them to the bigger version at some point (look at 00:16 secs in this video).


The bug in itself, which I have yet to capture on videos happens when selecting text with the mouse, sometimes the bigger version of the glyph is rendered and vice vera, creating a shifting effect.