Hi @cathy
Could you please try to sync the Local JSON files? This page should give you more idea about it: https://www.advancedcustomfields.com/resources/synchronized-json/.
If that doesn’t work, could you please backup the Local JSON folder and then delete it from your site? After that, please check the “Return Value” on the backend to make sure that it has “Image Array” enabled.
Thanks 🙂