I have a leadsheet written in Petaluma, with one player/instrument. When I add a new instrumental layout, addthat player and create a clef override (to create a bass clef version), the music font for both old and new parts and score changes to Bravura for no apparent reason. Using 3.5.11.1054…
Yes, I’m afraid this happens because Dorico has to add the new clef to the library of clefs in the project from the default library, and that includes the ‘Default music font’ font style. You can go to Engrave > Font Styles and change this back. Sorry for the inconvenience!