Unable to update letter Generation Configuration Based on Document Record Source

Summary:

Unable to update letter Generation Configuration Based on Document Record Source, while trying to modify person number auto generation method, Getting following error and when try to delete one of the records, it's not allowing to delete. There are only two options to choose and

Content (please ensure you mask any confidential information):

If I try to choose same value and chose No or yes different from other record, getting the below error.

Version (include the version you are using, if applicable):

24C

Code Snippet (add any code snippets that support your topic, if applicable):