Regression in symbolic colors in statustray plugin

While the option to 'Request symbolic icons' still seems to request the correct icons in git master aka 4.17.x, the icons are not drawn with the correct (aka foreground) color. Instead they are drawn in their original grey color (the color that is replaced by Gtk's CSS colors).

4.16.5

4.17.x

The themes in use were adw-gtk3 for Gtk and regular Adwaita for icons, but I've also reproduced the same behavior with Greybird and elementary-xfce.