The most likely cause of this is usually conflicts in field names, either with other fields on the same page or with WP reserved words. It you don’t see anything like this.
If it’s ACF5 can you export a json file of your field group and attach it here. It it’s 4, can you do an export of the field group and save it as a text file and attach that. Will make it much easier for me to test it out.
Welcome to the Advanced Custom Fields community forum.
Browse through ideas, snippets of code, questions and answers between fellow ACF users
2022 was a big year for Advanced Custom Fields, with more capabilities, a new generation of ACF Blocks, a refreshed UI, and a new home. Our year in review post looks at advancements we’ve made and offers a glimpse of the future. https://t.co/HahJUCcyH4