Very simple issue.
We have two dissimilar walls that are aligned look like this in plan:
We want to move one of the walls (brick) so that there is a 2" offset. But moving one of the walls, moves both the walls. Trying to align to a ref plane that is offset by 2", moves both the walls together too.
Selecting the wall, then selecting the Move command and then selecting the disjoin option in the option bar:
does the job.