Validation rule limiting which profiles can add values to picklist fields, later blocks users editing record at all when field is filled out, why?

Question

I have a validation rule on Opportunity that only Admin profiles can add values to certain picklist field.

As Admin I have filled out this field on several records, and now users are experiencing errors when later trying to edit the record in other fields because the picklist field is not empty and they can't save any other changes since it thinks they are trying to save the record with Referring Partner field out, which was not done by them, whats wrong with the Validation rule?

AND( $Profile.Name <> "System Administrator", $Profile.Name <> "Admin_CS", $RecordType.Id = "0120N000000kOIj", NOT(ISBLANK(Referring_Partner__c)) )

I filled out the Referring Partner and now other users cant change information in any other field.

Answer 1

Your validation rule is checking the existing data, so the user can't save as long as the rule matches. You need to add an ISCHANGED in there:

AND( 
  $Profile.Name <> "System Administrator", 
  $Profile.Name <> "Admin_CS", 
  $RecordType.Id = "0120N000000kOIj", 
  NOT(ISBLANK(Referring_Partner__c)),
  OR(ISCHANGED(Referring_Partner__c), ISNEW())
)

(The ISNEW prevents the user without access from creating a record with this value)