my $host_views = Vim::find_entity_views(view_type => 'HostSystem', properties => ['summary', 'name', 'config'], filter => {'name'' => qr/^$host/i});

    foreach my $host (@$host_views) {
        my $hostname = $host->name; 
         ...
    }

Works perfect for me.

But I'm using SDK Version 6.5. Can you just try an upgrade?