Great that it works again [:)]

As indicated in the help page about room modification (see 4th bullet), a ceiling follows sloping walls only at the last level. Remove level 4 in your file, and you'll see the ceiling you expect.
But as you know, sloping ceilings are not correctly computed as soon as the room shape becomes a little complex, so I would recommend to use other objects for the roof in that case, and hide the ceiling.