It will probably shed no light, but in IO::Zlib you can find this:

sub AUTOLOAD
{
    my $self = shift;

    $AUTOLOAD =~ s/.*:://;
    $AUTOLOAD =~ tr/a-z/A-Z/;

    return tied(*{$self})->$AUTOLOAD(@_); # <== line 566
}
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I'm no AUTOLOAD expert, but it could be that instead of Storable::fd_retrieve, the interpreter is trying to call $fh->fd_retrieve and AUTOLOAD does the rest. Try to disambiguate explicitly:

    $rep = Storable::fd_retrieve($fh);
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Hope this can help!