To make sure that the WPFC is indeed the one that causes the conflict, could you please try to reproduce the issue on one of the WordPress’ stock themes (like Twenty Sixteen) with only ACF activated? 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 even after you changed the theme and deactivated the plugins, could you please share the JSON export file of your field group so I can test it out on my installation?
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