This has happened to me a couple times this week. I'll be in the middle of a quest and I'll use a telepipe. Once I get back to pioneer 2 I'll do whatever it was I intended on doing. Then right before I go back to the quest I'll go to deposit some items or meseta and whenever I hit enter on deposit or hit escape to back out of the menu the game freezes for a second, the screen goes black, then the title screen comes up. I haven't lost any items they end up either being deposited or just staying in my inventory however I lose the progress on the quest I was working on.