Hi @mclambert
That’s because the relationship field saves the data in the database as a serialized IDs. If you want to query it, I believe you should do it like this:
'meta_query' => array(
array(
'key' => 'offre_liee',
'value' => '"' . $offre_id . '"',
'compare' => 'LIKE'
)
),
This page should give you more idea about it: https://www.advancedcustomfields.com/resources/querying-relationship-fields/.
I hope this helps 🙂
