System spacing changes unpredictable when adjusting Page Style

Issue type

Engraving bug (incorrect score rendering)

Bug description

In single system scores, vertical spacing doesn't change accordingly to the values given in Style / Page dialog.

• On first change of any vertical spacing value, the upper most system moves down by roundabout it's own height.

• It stays there, even if you reset to default values. As like top and bottom position were mixing up.

• This behavior doesn't switch back, even if you revert to default settings.

• It doesn't matter if vertical justification is enabled or not.

• If you reduce the systems spacing now, the gap between the both topmost ones isn't equal to the rest.
  That happend with a new file.

Don't exactly know if it's the same. Maybe more or less related:

When I tried to open a Score created 3 weeks ago with the previous version, it looked all fine.
I changed the Title font and with that change, spacing was reset to default value (vertical justification off, default 15sp).
Originally it was much smaller due to space limitations.
When I reopened the file I found, that even in Style / Page dialog the default value of 15sp showed up.
I can change this value - it works as expected when increasing it, but decreasing below 15sp has just no effect.

Steps to reproduce

1. Open New or existing Score
2. Format / Style / Page
3. Change Spacing Parameter, while have a look on top staff
4. Reduce Spacing to minimum

Screenshots/Screen recordings

First, Spacing of Systems:

Second: Score File with Spacing Issue
Bannerlied_A5.zip

MuseScore Version

4.2.1

Regression

Yes, this used to work in a previous version of MuseScore 4.x

Operating system

Mint Linux 20

Additional context

No response