Courtyard should allow some space around each component. When placing a single screw block you definately want his courtyard all around the component to make sure everything can be assembled later on.
Stackable Screw blocks however have special design sometimes small mortise / tenon joints for interlocking. Here the standard couryards overlap.
I would propose to manually exclude this DRC after you have checked the positioning (pitch) is correct.
According to Jeff Young there is a new feature that allows you to even add a comment that this DRC error has been checked and should be ignored see here