Nonexisting keysignature

1). You'll have to give your score a key signature, it doesn't matter which one except C major.

2). You'll have to cancel the key signature at the end of the page (look at Picture 1).

If you look at Picture 2, you'll see a "space" where a key signature could be located. MuseScore 3 treats it as if there is a key signature, when there isn't.