Hi @pastore1980
To clarify:
1. The above code is used int he single.php
template (view for a post)
2. The filter value is loaded via $zone_articoli = get_field('zona_per_i_pacchetti');
3. The $loop find all pacchetto
and ignores the filter
Perhaps you need to debug your code. Try removing the $zone_articoli
from the equation and hard code the meta_query.
Also, is the select field a single or multi select?
Thanks
E