Finally find a “bad” way to fix it.
This is for a client, I couldn’t wait so long…
I duplicated the fields group, and deleted the first one.
I had difficulty understanding the way of ACF works in the database, I was looking for the rules links, but there’s a lot of wp_meta keys which have been created. Fortunately (and a bit oddly) the duplicated group keep all the content which has been written on the different pages in the previous fields group, so It works now.
