Do not mark memberships as outstanding

I have a question regarding sync editor (7.1.1).

E.g. in the default AD template, group memberships are synced via the vrtMembersSID attribute in the group mapping, and are resolved to ADSAccountInADSGroup entries and so on.
For base entries (e.g. ADSGroup), we can specify the processing rule in the corresponsing workflow step, so we could configure that actual group objects should not be marked as outstanding. But the membership objects do not have their own workflow steps.

In the virtual property, there is a check box called "try to mark the object for deletion (outstanding)". It is not checked, but memberships still get marked as outstanding.

How can I influence the processing behavior for M:N schema type objects?