Pers.number already flagged for &

What causes this issue?

The personnel number you are currently processing has been flagged in
in table T77INT. The date of this flag does not match the date of the
action you have just executed.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Error message extract from SAP system. Copyright SAP SE.