Key signature applies only on first line

In Page view only the first line (before the line break) is updated when pasted a new time signature.
V 3.0.1.5087
- I created a score in c-minor (3 flat) (using the empty template and just adding more instruments)
- Dragged the 2-flat key sig from the palette onto the first bar
- The first key signature changed, but at the line break a new signature appeared.
Could not yet reproduce only happens with this score: https://musescore.com/bertalan-fodor/scores/5401485