Distance between systems can vary slightly due to skyline extension below system header
OS: Linux Mint 20.1, Arch.: x86_64, MuseScore version (64-bit): 188.8.131.528021370, revision: 3224f34
Open the attached score. Compare the distance above the chord symbols in system 2 with that above the chord symbols in system 3. The latter is slightly less but there doesn't seem to be any obvious reason why.