I've played three games today and two of them crashed. I supposed it happened when locking and unlocking within 10-20 seconds. The first time it crashed I lost the save, therefore I was unable to continue playing but it did keep track of my general level.
It was a little annoying considering I spent 4-5 hours on that game and it was just about to become interesting.
Three time, and it's not the locking-unlocking thingy. What is it! >_>
*playing on Galaxy S3*
Thanks for reporting this Manu! I think this might be a duplicate of - Lost save game after closing app (0000293), which I just filed. See this forum thread.
Sorry for the inconvenience!