Why logminer v$logmnr_contents.sql_redo does not use PK fields only for delete operation, even when

ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY) COLUMNS is applied.

For a table update DML, v$logmnr_contents.sql_redo where clause uses table PK fields only => good

Yet for a delete DML, the sql_redo where clause uses all table fields : why ???

As bad effect, If one table field is of type "long", such sql_redo can't be applied because of "ORA-00997: illegal use of LONG datatype"...

Some idea ?

Thanks