MS 3.6.2 serious sound issues

Hello friends! I'm working on a 2015 MBP with OS 10.14.6 (Mojave) running MuseScore 3.6.2 (latest update).

I hear sounds beeing playbacked but really badly! It does it both on veeeery easy scores (1 note!!) and more complex ones (big band).

What it does: it slows down the tempo, every note is seriously distorted, there are glitches and drops in the sound, and it seems like that when I move my fingers on the trackpad it's even worse.

Do you have any experience like that?

I tried to unistall it and re-install it. Same problems.
I never had these problems under precedent releases.

Thanks