I've had this happen three times and I thought it was worth mentioning.
What happened in each case was that I landed in an urban zone and went about normal business- sell off goods, refuel, repair, recuit, spice, and looking at available contracts. I then turned off my tablet for a few hours. When I revisit the game, usually after using other apps, my ship seems to reset to when I first landed- I have all my cargo as I did before selling off/buying. Morale and crew are the same as after I had visited the spice hall, but I had to re-do any repairs. My total money doesn't change after the "reset", but the quantities of goods available in the exchange was the same as after I had sold off my goods the first time. That is to say, in one instance I had originally bought out the supply of fuel (20), and when I returned to the game I had 0 fuel like when I first entered the port, and the exchange also had 0.
Like I said, just thought it was worth mentioning since it happened pretty much the same way a few times now.
Sorry, should've mentioned all those details. I'm running ST Elite v3.9.29 on my stock Samsung Galaxy Tab 10.1, on Android 3.1. I have an app killer installed that I barely use but I don't really use it on Star Traders as it doesn't take up much memory. If it's also worth mentioning I use a backup app to create a weekly save of the game.