Hi,
It actually is an intended feature
Many folks display only some non-musical text in a staff. Since Notation products' basic purpose is to give sheet music for .mid files, such "text only" staves are hidden on opening the file. They are still present in the file (you can view them in Notation Musician and Notation Composer, but not Notation Player) you just don't see them on the initial opening of the file.
ttfn,
Sherry