In the attached score the stem directions are wrong in e.g. measures 3, 6 and 7 in spite of being set to "auto". Trying to change them to "down" doesn't work. There are other instruments in the score set to "invisible" but I can't see a second voice that might be the reason for the issue.
I don't know, where the score originally came from and who edited what.
The intention of the invisible instruments is to have a leadsheet that could also be used as a playalong. Ideas how to achieve that conveniently are also welcome.