I just played a game against a random player (Game ID: 79926795), and clicking "Autoplay Treasures" during the buy part of my turn ended my turn immediately. This happened 3-4x during gameplay when I had different variations of coins (with and without Hoard). I also tried clicking every Treasure versus clicking "Autoplay Treasures" to no avail. I ended up resigning because I was so annoyed. I'm using the latest version of Chrome and I didn't have the same issue with the first game I played with the random player. What's happening here?
From a glance through your game log, what happenened several times is that you bought Villa, which then moved to your hand. You played the Villa then using Way of the Horse. This leaves you at 0 buys!
You used your "given" buy on the Villa, but since you didn't play it for its own effect, you don't have any buys now. Since you didn't use any other means of getting +buy on those turns (Hamlet, Pawn, Charm), once all your Treasures are in play, there is nothing else you can do (not even buy a Copper), so the game is automatically continued, which means the turn ends (unless there are Night cards or some Clean-up effects need to be handled).
This is IMO the reason Villa (and Cavalry) gives +Buy in the first place: Your second buy phase is pretty useless without any buys, which you just experienced!
Whoa! I totally didn't think about that. Thank you so much for the explanation and double kudos for such a quick response!!
You are not the first to fall for that, including myself. Since nothing in the game can take away your buys (well, except Mission for card buys), this is an unexpected behaviour for most players.