Four Measure Number Issues
The attached file, z.mscz, illustrates all of these.
1) Instead of measures that are multiples of 5, it is numbering measures that are 1 + multiples of 5. If you go to Format/General Style.../Measure Numbers and uncheck "Show first", it numbers the measures correctly.
2) Select a measure number and open the Inspector. The default vertical alignment is Align top edge. That can't be right. The third option from the left, Align baseline, should be the default.
3) Select a measure number and change its vertical alignment to Align baseline. Save the file, then close it and reopen it. The change to the measure number's vertical alignment was not saved.
4) Though you can modify an individual measure number's full set of properties in the Inspector, you cannot modify many of those properties in Format/General Style.../Measure Numbers. There is no way to set these in the current overall style. This is especially problematic for scores that have these properties set, but now they cannot be changed globally except in a previous version of MuseScore. Missing properties include:
b) x and y offsets
c) horizontal alignment
d) vertical alignment
e) Frame checkbox and, if checked, the rest of the frame properties
f) Circle and Box checkboxes