C-Major/a-minor and atonal key signatures cause other elements, like dynamics, to move up

Look at the sample score, the dynanmics at the start of the system and the next one. The one at the start is higher.

Move it sideways a bit and it'd eventually jumps down.

In a debug build switch on skyline then and see a small peak:

Culprit is the keysig:

      <Measure>
        <voice>
          <KeySig>
            <accidental>0</accidental>
            </KeySig>
          <Dynamic>
            <subtype>mp</subtype>
            <velocity>64</velocity>
            </Dynamic>
 ...

Remove those 3 lines and that jump is gone

Happens in 3.6.2, not in 3.5.2