App crashes during memory release
This usually happens when the device was running for a long time without reboot. Basically what happens is that iOS cannot find enough memory for System Status and kills it. In these cases it's best to restart the device because the same will happen also with other apps which need larger amounts of memory.
Personally, I'm not a huge fan of the "memory release" feature - I implemented it only to silence all the user's requests. Have a look at the documentation for more details: