Phrases and songs disappear

I've just started having this problem. Really strange. Up until now, I've had no problem using the sequencer. I'll load a song that I'm working on and notice several phrases missing. Things I know I didn't delete. Then when I went to the song list there were songs missing. I would say this qualifies as a serious bug. Has anyone else had a similar issue? This really sucks! I'm losing lots of good things because of it.