I haven’t noticed your topic back in January.
I’d like to say something regarding the video in your initial post.
When I assign a MIDI controller directly to a plugin parameter then Cubase will only record the midi controller into a midi part. It will not reach the automation lane.
Example for directly assigning a midi controller to a plugin parameter
So, if you can change the value of the automation lane’s parameter with a MIDI knob you must have assigned the knob to some sort of indirect control in Cubase. Maybe Generic Remote, maybe MIDI Remote Control?
It would be essential to know how and where you assigned that midi knob.