Listen to this, guys. I spent all day adventuring (4-5 hours) and got up to a 13M+ score. All my equipment had broke, so I was just about to go in to town after I finished the current round. I was in the middle of the boss fight and the dreaded "Disconnect/Connection Lost. Returning to town." message came up.
So I lost all of my EXP, most of my loot, none of my money, all the talisman (I had managed to get them all in the run) and none of my quests!
I kept myself from throwing my controller through the window, but I felt pretty sick. All I can say is this glitch is unacceptable, Atlus.
I am so sorry.