SP 2019 - Error - Multiple entries matched, please click to resolve.

Using SP 2019 on Prem and get the above error when editing an entry in a list using a "People" field.

When using quick edit, we can't fill down these same users, or even enter them and move off that row.

Then I link to the list via Access, I can see that there are actaully multiple entries in the user list for the user.

For example, some are:

Bob Smith