The Genius Loci node “Collector of Views” gives “null” for the views output.
I tried it in the current open project I’m working on, in a document opened in the background, and I tried it on a new empty project. The rest of the outputs seem to work fine, it’s just the first one for the views that gives null.
Tested on Dynamo 2.1, Revit 2020.
This screenshot is from a new empty project.