I don't think I saw this in RTM but it might be there.
Here are the steps to reproduce the problem.
1. Right click on your collection and select properties
2. Under membership rules create a new query for the collection
3. Type in the Name and set Resource Class to System Resource
4. Under Collection Limiting select Limit to Collection and browse to a collection to limit
5. Select Import Query Statement select any query to import and click ok
6. Now look at the Collection Limiting, is now set back to No collection limited
