So, this has happened to me at least twice.  I just finished doing some stuff after you going to look for the sword pieces and the drowned temple.  I had gotten the thief, did the event, and even got both pieces I needed to enter the drowned temple.  I then headed back to Tristam and logged off for the night.  I come  back on today and now I am even before I hit the temple for the first time. I still have my achievements and the thief is still in town but progress is even before I get to the thief.  Anyone else here experiencing this? 

@Sammo21: You have to do that all in one go, due to how the map resets. It gets very annoying during act 3

I love the game to death but it has got some issues.

OK...I was fine with the fog of war type stuff coming back but the fact that progress resets is pretty ridiculous.

Basically when you log off you are going to restart at whatever the last checkpoint you passed was. However items, gold and XP are saved pretty much in real time, or a close to it as to not really matter. In theory not too bad a system, however at some points the checkpoints are too far apart. Hopefully they'll tweak them in a patch or server update once the more serious issues are addressed. IMO it should checkpoint whenever entering/exiting a dungeon or new level of a dungeon, whether story based or not. Ideally also whenever you use a town portal or waypoint. Well maybe not town portal as that could be open to exploiting by making a check point right before a boss then getting his loot, quitting and reloading.

Think of some segments of the Act's as a "Gauntlet Mode." You have to complete the entire piece before a checkpoint clicks. Before you log off, make sure you noticed a recent "Checkpoint Reached" or you'll be starting at a prior point.

OK, that makes sense.  Slightly weird, especially considering I am technically online all the time with the game.  Still, it hasn't dampened my experience with the game.  I'm about 1/4 of the way through Act 2 and absolutely love it.  Been playing a Monk and love it.