Tremolo affects skyline of non adjacent single line staves above
See https://musescore.org/en/node/285302 for discussion and sample file.
In the attached score, enter tremolos on the bass or cello. Doing this causes the distance between the single lined percussion instruments (cymbal, Bass and snare drums) to increase as though the tremolos were on the staves immediately below.
The workaround consists of using the Fixed staff spacer and turning off Auto placement for the dynamics. Not a good combinations of workarounds, so I set the severity to major