I created two shared parameters and saved them. I then created a custom room tag using the system room parameters and the new shared parameters I created. The shared parameters appeared in the properties window when I selected the room. I was able to enter data there. I created a room schedule and everything displayed correctly including the shared parameters. I then linked the shared parameters to project parameters. The room tag shows blue ? marks when I select the room tags, and blanks when I unselect.
It appears that Revit has the data in the shared parameters, but somehow fails to pass that data to the project parameters to display in the room tag. What am I missing here?