create a layer, set it to video input, make it small, place on left side of screen
In "Filter (layer)" add CI Hue Adjust and set it so the knob is pointing left
duplicate the layer, move the copy to the right so you can see the two layers side by side
change the Hue Adjust knob to point right, observe that the hue of the right copy doesn't visibly change
select layer 1, disable the Hue Adjust feature, and observe layer 2 visibly change hue.
Whenever the hue filter on layer 1 is enabled, the filter on layer 2 is forced to the same control values.
This seems to be the case for all core image filters, not just Hue Adjust.
But, if I switch the media to a testcard, the problem is not observed (it is possible to have different control values for each layer)