Ok, I tried to downgrade to release 3.6 and the above code works well. In simulator and in real devices the songs play fine.
So, it’s definitively confirmed it’s an issue of the latest 3.7 / 3.7.1 release of monogame.
I am very curious to discover the reasons of this bug…
Nobody can help us?
@Benjamin_W Your work is really impressive! It overcomes my current needs, but I will preserve it for next projects 