[voice]
I think it has something to do with the stabilizer machine that keeps things running around here. We're not really supposed to be here--we're forced to stay here. We're supposed to be back home, and when it glitches it tries to fix it by sending us back, but it can't, so we end up with new memories instead. Or something like that.
[Or this is how Josak tried to make sense of it himself. Why else would they randomly end up with memories of being home when they never even left Marina? Why would people randomly disappear and never come back? He gives a sheepish laugh.] You'll have to ask one of the smarter ones around here who know more about it than me. I just know a few people it's happened to.