Replicate: play any beatmap with forced skin (it may also work with skins put in beatmap folder), open Chat and click "add channel". Buttons are these from forced skin, not the one user has set in Options - which may be intended behavior, but is weird compared to fact that custom skin isn't used on ranking screen.
Screenshot: http://osu.ppy.sh/ss/53. I use my own skin based on default one, I was playing Don't Stop me Now (EBA skin).
Screenshot: http://osu.ppy.sh/ss/53. I use my own skin based on default one, I was playing Don't Stop me Now (EBA skin).