External Party Add-On; External Party form, General page; Circular reference occurs when adding a parent that is the parent of the current record.

A circular reference caused the following error:
"Not Responding" when saving an External Party or trying to open the External Party or Account form.

The following situation would cause this error:
External Party B has no parent.

External Party A has a parent of B.

External Party B is then updated and the parent set to A.