When importing an authority record via z39.50, the authid assigned to the record by Koha doesn't get put into the 001 tag. The authid *is* correctly assigned to the authority record, it just doesn't get put into the 001 in the marcxml. Using z39.50, the authority record retains whatever data was in that 001 field originally. When one of these authorities is linked, the actual authid is used in the link to the bib record.
This is no longer true, the 001 is replaced on saving the record.