When using the 'Intersect' list operation, Mendix uses the object(s) from the second variable you specify when creating the result-list. It would be great if the RefGuide would be updated to include such subtleties, as it matters a lot when one of the two lists comes from the DB and the other doesn't, meaning one can contain items in an older state than the other. The same goes for a lot of other items in the RefGuide btw, they can use a bit more specification on how things exactly work.
This is a remark worth file a support ticket for IMHO, or add this as an idea for the idea thread on the forum.
I do agree that elaboration of the documentation would be a great help.
Erwin 't Hoen
You can create comments on the documentation pages. I think that would work faster than creating a support ticket.