Heh, ce_localplayer_track_spec_target seemed to have stopped working in STV demos out of the blue today. It was working earlier today, but somehow now it doesn't track who you're spectating. ce_localplayer_player is stuck at 1 and doesn't change. If you turn it off and set it manually it works.
So weird, no updates or anything today... Maybe I've missed something? Is this still working for others?
EDIT: So this is happening on newer demos. On older demos this is still working. From submissions this looks to be from mid May onwards, so May 17 update most likely.