Not sure how far back this goes, I only have 7.65 & 7.66 executables saved. Wrapped lines seem to have a bizarre color to them where the foreground and background are identical.

Heres the test alias Executed with:
/testwrap this is a test and only a test of a super long line here that should wrap
alias testwrap {
  window -dpf @A -1 -1 320 240
  var %x = 1 , %y = $wrap(4<hmm4> $1-,$window(@A).font,$window(@A).fontsize,$window(@A).dw,0) , %height = $height(text,$window(@A).font,$window(@A).fontsize)
  while ($wrap(4<hmm4> $1-,$window(@A).font,$window(@A).fontsize,$window(@A).dw,%x)) {
    echo $color(normal) -s *** DEBUG: $v1
    drawtext -np @A $color(normal) 0 $calc(%height * (%x -1)) $v1
    inc %x

And here's a screenshot of what's happening. There are no color codes where the line separates, only the very beginning, [k4]<[k] AND [k4]>[k]...

[Linked Image from]