This code provides details of where the problem occurs:

my %comp = (
    'Ad1' => [ qw( 0A78 0A9E 0AB9 0AC0 ) ],
    'Ad2' => [ qw( 0A78 0A9E 0AB9 0AC0 ) ],
);

my %device;
my @locations = sort keys %comp;
for my $location (@locations) {
    for my $dev_name ( @{ $comp{$location} } ) {
        $device{$dev_name}{$location}++;
    }
}

my $expected_locations = join ',', @locations;
for my $dev_name ( sort keys %device ) {
    my $actual_locations = join ',', sort keys %{$device{$dev_name}};
    next if $expected_locations eq $actual_locations;
    print "ERR: '$dev_name' only found in '$actual_locations'\n";
}
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By the way, if ( scalar keys %comp > 1 ) {...} can be reduced to if (%comp) {...}.