Last week I had an issue with 5.7.11 which broke several websites of mine with all different issues, but now on 5.7.12 it breaks a specific post object field.
I’ve manually downgraded to 5.7.10 and without doing anything else it works perfectly again. The field in the wp-admin was empty and when reverting back to 5.7.10 the field was filled again with the content that was there before.
I have no idea how or what to test, but I hope that telling you that version 5.7.10 works perfectly.
I’m having the same issue. One field (repeater with three sub fields) disappeared when editing a post. Field looked fine in the ACF config. I’m using json exports if that helps.
Reverting to 5.7.10 fixed the issue for now.
