Can't find any BTB slayer matches in Halo 1 or 3

I’ve sat waiting to find matches in Halo 1 and 3 BTB in social games for about 8 minutes each, but can’t seem to find any matches. It usually takes only a minute or less, and I can find 4v4 slayer games in the same titles no problem.

Are those particular game populations low or is something not working as intended? Can anyone else confirm if they can get H1 and H3 8v8 slayer matches?