Let’s say it as it is : any attempt to use NRPN as anyone would expect is broken in Cubase and this, since countless years. Even in the Generic Remote Definitions, trying to use Ctrl-NRPN as MIDI status option of a controller won’t work.
I have read here and there that a new ‘API’ in development might solve many of the remote control issues. Crossing my fingers, but from what I see, this is still vaporware.
Meanwhile, I use NRPN messages strictly for remote controlling Cubase with the endless knobs of my MPD32 controller. And to make it work, I have to use this convoluted workaround, even nearly eight years after having found it…