Treble clef being forced although I indicate bass clef (after save/close then open score)
Two-part music. Top part is for soprano recorder; clef is treble 8va alta. Bottom part is for bass recorder; clef is bass 8va alta. For the bottom part, I indicate bass clef 8va alta, and this works, but after saving/closing score and reopening it, MuseScore 3 forces a treble clef 8va alta (followed by a clef change to bass 8va alta). The weird thing is, this behavior only happens on some of the (similar) pieces I'm working on, but not others; I'm sure there is a reason for this behavior driven by the score's data, but I have yet to figure it out. Also, when I look at Edit -> Instruments, I see that instruments are pre-assigned clefs; the recorder instrument is pre-assigned treble clef 8va alta; I have not been able to change this to the correct clef for a bass recorder. So, in short, how can I keep MuseScore from forcing a treble clef for a part when what I really want is a bass clef? Thanks for your help.
OS: macOS Mojave (10.14), Arch.: x86_64, MuseScore version (64-bit): 18.104.22.16843, revision: 58dd23d