This error occurs when a record is created from a relationship, both have the original address moved to alternate, and the alternate address is deleted from the first record before address sharing is stopped.
This is resolved in 7.96 patch 13, released in September - October 2018 and applied to databases in Blackbaud Hosting Services. If your database is installed locally, download and install the latest version and patch, if applicable.
Steps to Duplicate
From a constituent record (Record A), create a relationship
During relationship record creation choose to copy the address from Record A
Once the relationship has been created and saved, enter the relationship and create a constituent from that relationship record (Record B)
Once complete, in Record A, create a new address and make that preferred. Do the same thing for Record B.
Delete the address that is now listed as alternate on Record A, do not stop address sharing before hand.
Once the record is deleted, enter the relationship from record. Attempt to make an edit to the address
Expected result: To be able to make edits into the address and save Actual result: The process goes through the motions of the edit but when reentering the record, the address doesn’t change