Grand Theft Auto V is not $US20 on Steam right now. Despite multiple awfully misleading listings on GTA's Steam franchise page (they're for cash card bundles; no game), it's still at regular price. Suddenly last week's GTA price shenanigans don't look so benign.
GTA V's price also shows up as $US20 if you search it on Steam right now. Obviously I can't say for sure what Rockstar's intentions are here -- this could be another honest mistake -- but this sure looks scummy. It's apparently been showing up this way all morning, too.
Thanks for the tip, Sean Cox.