Weird tempo setting
MuseScore 3.6.0
Starting a new piece in 12/8 time, I set the tempo to 58. The setting in the piece came up as a dotted quarter = 38.6667. Strange! I haven't tried to reproduce it. Just passing on what I observed.
The ratio 58 / 38.6667 is 1.50. That may suggest what happened.
Comments
That is exactly what does happen and what should happen: The input field doesn't really take Beats Per Minute, but Quarternotes Per Minute. So you want to enter 87 there, resulting in dotted quarter = 58