Windows 10, Cubase 9 upgraded to Cubase 12, Focusrite 6i6 Scarlett 2nd Gen. interface.
After upgrade audio input is always ON even when changing from audio track to MIDI track.
Possible solution: Acquire Focusrite 2i2 Scarlett 3rd Gen. which has a “direct monitor” button. (No problem with Cubase 9).