I was speculatively looking around for awards to/from South America about a month ago and there were reasonably often options with UX, the last couple of weeks there's been nothing - and indeed something like MVD was returning no options/spitting me back to the search screen. It could be UX removing inventory generally, just for FB or it could be an IT issue - but I do think OP is probably noticing something more than just all the tickets having been booked.