I have an arrangement for an accordion band, 3 parts plus a bass staff that goes in every part, so every individual sheet has 2 lines.

I'm having an issue with only one of the 3 parts. The part is adding this middle line, which is a clone/ghost of the line above it, but with no articulations/markings. I can't delete/hide it, because if I do, it hides the top line as well, which is a problem because that's the line I want to be displayed. I tried removing all the instruments from this part and starting over reassigning the staves, same problem crops up. All this leads me to believe it's a display issue of some kind, rather than a part creation issue.

I could create a new template, but I spent a lot of time making this one so I'd rather not if I can avoid it. 

Finale 27.2.0.144, Windows 11.