Hi-
That definitely sounds like a bug in LayOut. You may be able to reduce your exposure to the issue by regularly manually saving the file to a backup file name, but that's an annoyance that shouldn't be necessary. I'd be very interested to get a copy of your corrupt file, especially if you've found a way to reliably reproduce the problem.
Also, for faster response from the SketchUp team I'd recommend posting in the official SketchUp forum (forums.sketchup.com). Except during a release, I tend to only have the time to read SketchUcation a few times a month.
Thanks,
Marc