Hey, Fabio.
Just tried again to confirm: no, that did not work for me.
I re-copied the “bad” Defaults.xml over my fixed (freshly created) one to recreate the original issue (which it did).
I then removed the Stereo Out 1/2 bus and created it. Still no sound.
I then relaunched Cubase, still no sound.
I also tried removing and naming it something different than “Stereo Out 1/2,” but no sound from that, either.
The only solution for me is to delete Defaults.xml and allow Cubase to freshly create it.