When importing a list of spouses, you may encounter the error Constituent entered has an existing spouse that is different than the spouse entered in the row event though the spouse is the same.
If you experience this issue make sure you're using the Spouse and Spouse Lookup ID field in your import process. These are the fields to use when associating a spouse with a constituent and not the spouse first name or spouse last name field. These fields will search for spouse records, otherwise the spouse entered in the batch will be treated as a new record.
Steps to Duplicate
After running your Constituent update import process
From Revenue, select batch entry
Select your import batch
See that constituent with spouses name has the error Constituent entered has an existing spouse that is different than the spouse entered in the row