I don't totally understand this field, would it make sense to use the SetMarcUnicodeFlag function found in C4/Charset ?

Doing something like:
if ( $is_a_modif ) {
    ModBiblioframework( $biblionumber, $frameworkcode ); 
    ModBiblio( $record, $biblionumber, $frameworkcode );
}
else {
    eval { C4::Charset::SetMarcUnicodeFlag( $record, $frameworkcode )};
    if ( $@  ){
        warn "ERROR when setting Marc unicode flag: " . $@;
    }
    else {
        ( $biblionumber, $oldbibitemnum ) = AddBiblio( $record, $frameworkcode );
    }
}

where the code we have now is simply like:
if ( $is_a_modif ) {
    ModBiblioframework( $biblionumber, $frameworkcode ); 
    ModBiblio( $record, $biblionumber, $frameworkcode );
}
else {
        ( $biblionumber, $oldbibitemnum ) = AddBiblio( $record, $frameworkcode );
    }
}

Adrien doesn't work anymore at BibLibre.
Unassigning this bug to give it more visibility.

(In reply to Victor Grousset/tuxayo from comment #2)
> Adrien doesn't work anymore at BibLibre.
> Unassigning this bug to give it more visibility.

Victor, would you be able to verify that the bug still exists? It seems related to UNIMARC as 100 has a different meaning in MARC21.