What I think is that you don't have the format that was used on the drawing accessible. If the drawing was "saved with display" you will see the format when opening but after the drawing updates, the format will not be there. At least that is my guess based on your description of the problem.
To verify, look in your working directory or workspace if in pdmlink for the clients format. You can find the name of the format in the layout tab under sheet setup.