When merging two constituents, sponsorships and the Sponsor constituency are transferred to the target record. However, there are instances where an incorrect end date is added to the Sponsor constituency. This occurs under the following conditions:
-The target record has a Sponsor constituency and active sponsorships. -The target record has previously had a sponsorship that was transferred to a different sponsor (thus, that specific sponsorship has an end date)
The end date that's incorrectly added to the Sponsorship constituency on the merged record is the end date for the transferred sponsorship that was end dated.
An additional problem that arises from this issue is that if a sponsor has multiple transferred sponsorships on their record, they may have multiple sponsor constituencies added to the merged record.
Download and install the latest patch, which contains all fixes from previous patches. If you are running an older version, download and install the latest version and then the patch.