MS3: Line color not being saved.
OS: macOS 10.14, Arch.: x86_64, MuseScore version (64-bit): 184.108.40.20639, revision: 06a66a2
Make a "note anchored line" (or any line as far as I know). Set its "line color" (and its "element color" -- what is this?) to Maraschino/red. Save the file. Close it. Reopen it. The lines are black/Grey.