Using an effect mask on keying effect results in the other layer doesn't respect its overall alpha

How to reproduce:

1)get a greenscreen footage

2) track a garbage mask

3) apply color range effect > key the footage

4) set color range's effect mask to that mask

5) duplicate layer, remove all effects and masks on a duplicate

6) apply on it set channels (or set matte) pointing to the second layer using effects and masks

7) Switch to solo to view that the alpha is ignored