Problems during migration from SQL Server to MySQL via MySQL Workbench
I think F3B3B4AF is beyond the end of established UTF-8 characters.  Perhaps MSSQL allowed, but MySQL did not.

Please provide SHOW CREATE TABLE for the target table.  It had better be using utf8mb4 for the target column.

Do any of these look correct?

                              gb2312, gbk   6  2 '蟪疮'
                                    euckr   6  2 '車눕'
                                     big5   6  2 '馧敞'
                            eucjpms, ujis   6  2 '鶻姦'