I played alone on our shared world for about 2 hours earlier. I unlocked and scanned the ash cement, then made a big bridge that took over an hour and a half to make. I superquit and it SAID it was going to make a save before I exited. Not only did it not make a save then, when I loaded it didn't even load one of the dozen auto saves it had made during my time. Instead, it reset to just before I took the ash cement out of the oven.
Are you SURE this game is ready to leave early access? Because shared worlds certainly have been finicky and you don't offer any way to load other saves if your game screws up.