When creating new records from the Relationships tab, contact information is copied from the existing record to the relationship's record. If contact information is changed, added, or deleted on the relationship record before it is saved and closed, the changes are reflected on the existing record.
We addressed this issue in 7.87, patch 6. In Education Edge databases that are integrated with The Raiser's Edge, in patch 6 and higher, contact information will no longer be copied when addresses are copied or shared. Contact information must be added on each record individually.
Alternate Solution: Save and close the relationship record before adding, editing, or deleting contact information on the relationship's record.