UPDATE: I did some more searching on the internet and found that it appears to be paid Market apps that this happens with. Some have wiped market data or uninstall the Android Market (sorry, Google Play just DOESN'T work and sounds bad so it's STILL Market to me). I just rebooted to see what would happen and sure enough, my apps disappeared again. Not all of them, but a majority of them. I cleared out the data for Google Play, rebooted and it didn't fix the issue.
Makes me wonder if the market app in the gapps flash image is causing the issue?
Is this what you found?
Wonder if related: http://www.androidcentral.com/paid-apps-disappear-google-play-store
Is this just a reporting thing from Titanium, or does it look like it's not even installed if you go look for it again in Market (i do it too).