Recently the tab character has been extented to be displayable inside a window, before the tab character would just not be displayed visually speaking.
This is problematic for debugging scripts, but even for normal display of line, scripters are used to /echo unknown/dynamic string to see what it contains and the new display of tab does not help at all (though there are other characters which still won't display, mostly non printable character such as carriage return or linefeed).
/drawtext $wrap $width and $height all have an option to handle the processing of tab characters, /echo and others displaying functions (/filter etc) should also get an option to handle them.
The way tabs are displayed currently feels wrong anyway, the tab does not expand according to the text and act like a tabstop :
//echo -a $str(Z,N) $+ $chr(9) $+ Z
As N gets bigger, the display will end up not displaying the tab at all, selecting texts shows there's no gap, I'm not sure if this was intended or if it's a bug.