It does not happen all the times I quit Cydia, but it happens at least one out of three. After I quit Cydia and my iPhone goes to sleep (locked, black screen), and I don't use it for a little while, there is still some process alive while the iPhone is supposedly 'asleep'. How do I know? Battery goes down, usage time goes up for all the time the iPhone was supposedly 'asleep', iPhone is warm as if I have been using it all the time. I run top, and it seems that springboard has been active all the time the iPhone was 'asleep'. I looked into the syslog file, and there is activity during the downtime. Does anybody know how to prevent/fix/recognize this problem not after the fact but before it happens?