This is very unfortunate. I have tested the same behavior with a Behringer X-touch. The issue is that because Surface Reader uses virtual midi cables between the control surface hardware and the application to then get the screen reader to read these messages as intercepted, by not being able to disable the midi ports in both the midi setting dialog and in the hardware dialog,The midi connection creates a midi loop. So, the result is that you get control surface faders moving involuntarily because they are receiving unwanted midi messages from the loop.
This looks like a bug in the software. Magix can fix this though by allowing the user to select a checkbox to say that if midi ports are disabled in the midi dialog box, they should also be disabled in the hardware dialog box.
Again, it is very unfortunate and a big negative not being able to use surface reader.