UPDATE: Looks like I have a GIT merge conflict message in my JSON file, that was preventing it from being loaded at runtime.
I’m seeing this same behavior on a “Page Link” field type, when I rely on the local JSON to load the field sets at runtime.
When the field groups are loaded from JSON at runtime, I get the ID of the page when using get_field. When I’m using a “synced” fieldset, I get the URL of the linked page.
It seems the issue is related to return format differing depending on how the field group is loaded.
Seems to be an issue with other field types too: http://support.advancedcustomfields.com/forums/topic/json-not-syncing-image-field-return-format/
