Unison Lines Causing Playback Distortion

This topic seems to have been mentioned on https://musescore.org/en/node/259946 about a year ago but the issue might not be exactly what I am experiencing.

Basically, the issue here has to do with the playback of unison phrases played on the same instrument. I'll leave an example. Title.mscz

Whenever you have phrases that are played in harmony as opposed to unison, you get a rich and full sound (as far as a MiDi will go, anyway). However, when you have a unison phrase, the sound produced in playback sounds weaker and also seems distorted, as if someone is muffling and un muffling the sound in a constant loop.

This seems to happen in brass instruments only as far as I can tell and It can be frustrating because sometimes the notes will actually sound an octave above for a brief period time due to this weird issue. There seem to be two workarounds, one is to alter the tuning, and the other is to place an invisible pianissimo dynamic under one of the parts. Both are time-consuming, as you have to alter these at points of unison, which will change at various sections of a score.

Is there any way to fix this to where when a unison is presented, the playback is just the sound of one part but at a projected volume? Or is there also a way where when two instruments of the same midi timbre play the exact note, one of the parts become slightly out of tune to mimic real life playback?

I'm not an expert, so I don't know if there are any underlying problems surrounding this, but if there is an easier workaround that takes less time, that would be helpful as well.