Color of layout indicator text is green when antialiasing in font.conf is turned on

[max-dw-i]

Expected behaviour

The layout indicator text should be the same as the theme text color.

Actual behaviour

The layout indicator text is green'ish with antialiasing turned on when text is light (when themes with the black text are used everything is ok).

Steps to reproduce the behaviour

Make a font config file in ~/.config/fontconfig/fonts.conf with antialiasing turned on:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
    <match target="font">
        <edit name="antialias" mode="assign">
            <bool>true</bool>
        </edit>
        <edit name="hinting" mode="assign">
            <bool>true</bool>
        </edit>
        <edit name="hintstyle" mode="assign">
            <const>hintslight</const>
        </edit>
        <edit name="rgba" mode="assign">
            <const>rgb</const>
        </edit>
        <edit name="autohint" mode="assign">
            <bool>false</bool>
        </edit>
        <edit name="lcdfilter" mode="assign">
            <const>lcddefault</const>
        </edit>
    </match>
</fontconfig>

and that's what I get:

MATE general version

1.24.1

Package version

libmatekbd v.1.24.1

Linux Distribution

Tested on Manjaro and Ubuntu MATE 20.10

Link to bugreport of your Distribution

Not distro-specific

P.S.

It's not the first mention of the bug: https://github.com/mate-desktop/libmatekbd/issues/28#issuecomment-301036883