Random Object Deletion

#1
I just downloaded the latest Maintenance Release of CMS PE+, and was trying to set up some layouts using the Layer States Manager, and noticed that I couldn't get some things to show up on certain layers. I went back to the Model tab, and discovered that those objects had simply vanished. Other objects had changed layers or moved.

I was able to find some backups and started again. Same thing. This time, whenever I made a change, even a small one, I saved the file. It seems that when objects disappear, the file gets bigger. So they might still be there, but I've had no success in making them visible, regardless of layer settings re frozen, visible, etc.

Thoughts? I may go back to the previous version to see if it solves my problem.