Switch to variable volume control locked

i am using the iOS app.

I tried to test using my bluesound node icon as a preamp and wanted to change to variable input after using it fixed mostly until now. I found that the setting to switch was deactivated. The only way to get the switch to work was to reset the settings. It worked then. I played around with it for a while and switched to fixed again. Now it is locked again. Is there a logic I don’t understand to why it lockes?

I also noticed other odd behavior in the settings area. The switch for tone control was also gone completely, after the reset is was there, but when activating the sub controls for bass and treble did not appear. 
when activating the subwoofer also the submenu for the crossover did not appear.

i checked this for my node 2i as well and all the above behavior exist also there.