I’m afraid I couldn’t find anything wrong with your code. Is it possible that you use a cache plugin? If you use it, could you please delete the cache and test it again using the private or incognito mode on your browser? Also, could you please try to reproduce the issue on one of the WordPress’ stock themes (like Twenty Sixteen) with other plugins deactivated? If it disappears, then you can activate the theme and plugins one by one to see which one causes the issue.
If the issue persists, could you please open a new ticket and provide temporary admin credentials to your site? You can open a new ticket here: https://support.advancedcustomfields.com/new-ticket. Don’t forget to explain the issue again or provide the link to this thread.
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