I use Adobe Illustrator extensively for mobile development. For example, for Android app, I have many illustrations with different densities and sizes. I use many effects such as outer glow, round corners and such. However, sometimes, when I close the .ai file and re-open it later, I found all my objects expanded. Effects are expanded. For example, the round corner effect is now expanded and I cannot re-size any object.

I am using a MacBook Pro. I am suspecting both Time Machine and Dropbox. As much as I can recall, it also appears with CS6 version, not CS5.