Brush mask copy shifted right and downward after installing the Lr Classic 14.2

This is the correct behavior. 

We shift mask components when they are duplicated because otherwise, their pins would be in the exact same spot, and it wouldn't be obvious which one you were selecting. It's also likely that duplicating a mask component is to change which part of the photo the mask group that it belongs to will adjust (in other words, move it to a different spot).

We don't do this when duplicating mask groups because you only see the pins of components from one mask group at a time, so there's no conflict in that respect. Also, duplicating a mask group is generally done so that different adjustments can be applied to the same or similar masks. A good example is the duplicate and invert mask group workflow, which is used to apply a different adjustment to the inverse of a mask group that could be a complex collection of mask components.