I have a Template I made with a Colour Schema.

The Area Schema is Rentable - one of the default Revit schemas.
I have a Shared Parameter I have attached to Areas in the Model - alternativeAreaType.
I have a Colour Scheme I apply to a View Template that colours based on values of alternativeAreaType.
Colour Scheme Location is set to Background.
View Range Bottom and View Depth are both 0 relative to the Associated Level of the View.

It was working fine for the first few days of Model usage - then it developed a problem. The colours are still applied but they are now obscured by Floor elements. If I hide the Floors in the View Template, the Colour Fill is visible. If I change Location to Foreground, it seems to colour Masking Areas within Families. Rooms in the View Template are visible but not Filled.

I did change the Elevation of the Levels that host the Floors (and the Areas, I guess). But at least some of these areas were drawn after I changed the Levels so I don't think that's it.
The floors are inserted with Offset of 0.0
Computation Height for the Levels is 0.0

As I say, it was working fine for a while and then stopped ... and I don't think it was when I changed the levels I. Of course, I did that in a Section View and it may have been a while before I was looking at the Plans again.

Anyone experienced something like this? Help!