Canot get rid of treble clef

Hi,

can someone me help to find what's causing this problem?

I have a stubborn treble clef in the very first measure of the lower staff and whenever I change it to bass clef, once I reopen the file the treble clef is there again. Drives me crazy really...Any idea what causes it?

I have two observations:
1.) It seems that in the instrument view the lower staff is set to treble clef as default. Can this be the problem?
2.) Or maybe it is causing the very first barline. When I set it to invisible the treble clef always appear there when I reopen the file (sigh)

the score is here:
https://musescore.com/user/39454580/scores/6893704

Thanks for any help.