This is not a problem on Cubase 11 Pro. Every single time I press a piano key the mixing console comes up in the DAW or another example is when I press a key it changes locators on the DAW or basically does something else. Essentially it is literally acting like an actual keyboard.
I am at a complete loss here on this and have spent 4 hours already trying to get it to work.
I would go and get this tool. Install it, and see what is really happening.
Unplug all MIDI devices except for the one. See what ports are available in MIDIOX, if there are more than expected, you may have found your problem. If not, then try the one port out in MIDIOX.