Invalid byte sequence when importing Oracle BLOB

Hi,

The source is an Oracle 12 db with this encoding:
NLS_LANG = AMERICAN_AMERICA.AL32UTF8
NLS_NCHAR = AL32UTF8

The destination is an (RDS) Postgresql 12.5 with encoding UTF8, and is being 
loaded through COPY commands generated by ora2pg.

The source table has a BLOB column (I think they are scanned images) which 
I'm loading into a Postgresql bytea column.

Seven times out of about 60M rows, I get this error:
Psql:909242: ERROR:  invalid byte sequence for encoding "UTF8": 0xed 0xaf 0xbf

Is there anything I can change on the Postgresql side to make these records 
import correctly?

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