Похоже что надо дропнуть и создать заново индекс

Error 644
Severity Level 21
Message Text
Could not find the index entry for RID '%.*hs' in index page %S_PGID, index ID %d, database '%.*ls'.

Explanation
This error occurs when the nonclustered index indicated by the index ID is in error. The corruption is detected when a process tries to delete a nonexistent row.

Action
Execute DBCC CHECKDB without a repair clause to determine the extent of the damage. Then, execute DBCC CHECKDB with REPAIR_REBUILD clause to correct the damage. If problems persist, either drop and re-create the index (as shown below) or contact your primary support provider.