I'm new to after effects.
Suppose that we have a solid layer. create a rectangle mask with blending mode set to Add. duplicate this solid layer and invert the mask in this layer. now we have something like this:
we have transparent space/crack along the mask path. these is no mask feather that can cause this problm. I set preview resoloution to quarter so it becomes easier to see. I know that this problem could be solved by expanding one or both masks.
my question is why this is happening? and how to fix it without expanding masks?