I’ve already searched a lot for this problem and cannot find a solution.
So, I am using a theme that comes with ACF Pro and I have some Relationship fields in some custom post types (CPT). No problems whatsoever on any CPT except one (which I find it weird)…
The thing is, I had a previous ACF version (when I first bought this theme). Recently I have downloaded an update for the theme and it came with a more recent version of ACF Pro (v5.3.5), so I upgraded it.
I don’t know why but I tried to add another Relationship field to a CPT (it’s already one there and some other fields as well) and, in that other relationship field that was already there it shows results, no problem at all, but not in this new one…
What I have tried so far, with no results:
– changed from “object” to “ID”;
– leave only one relationship field in that CPT;
– only change the post type for that “old” relationship field;
– manually selected taxonomies for the relationship field;
– added more than one custom post type to that relationship field;
– reinstalled ACF;
– checked for JS errors (nothing);
– checked for PHP errors (nothing).
But, the weird thing is, for that specific CPT, if I use a different field like “post object” it also doesn’t show any info…
But it works on any other CPT, except on this one. 🙁
For something like that, I suggest you open a new ticket instead and provide temporary admin credentials to your site in it. You can open a new ticket here: https://support.advancedcustomfields.com/new-ticket. Also, please don’t forget to explain your issue again.