For anyone who comes across this, the best solution that I found was this tool: https://github.com/mcguffin/acf-quick-edit-fields
This saved me an hour or two of manually updating 181 posts. After installing that plugin, I edited the ACF field and checked off the option “Allow editing this field in Bulk edit mode” then I was able to bulk edit the posts and update the field.
Please help with this! This is a big issue for us. As rdm mentioned above, it appears that the mce_external_plugins filter is not being run on the WYSIWYG field. Thank you for your help with this!
For anyone who may run into this issue, I figured out what was happening for me. I was using the Local JSON feature and for some reason it wasn’t updating the JSON even though my permissions were correct. I deleted the JSON files and it solved my problem. But then I had a new issue because it still wasn’t creating JSON files, and I solved this by using the save_json filter documented on this page: https://www.advancedcustomfields.com/resources/local-json/
I hope this helps someone! I love ACF but this was a very frustrating experience for me.
I am having this same issue and I did duplicate a field and drag it to another layout. Is there a fix or workaround for this issue other than manually re-creating these fields? This is a complex flexible content group and I’d rather not have to manually re-create dozens of fields. Please help!