The point of exporting the field group, in ACF4 is to put it into PHP. At that point you need to delete that field group in the ACF group editor and from that point on you make changes to the field group by editing the PHP, not through the ACF editor. You do this to build an application that does not require the field group recreated, for example if you are creating settings for a theme. When you distribute the theme.
In ACF5 you can export a field group and then import it into another site, as well as the benefits that I mentioned above.
If you want to build field groups and have access to editing them AND put them in to a PHP file then you need to have 2 sites. One for building the groups and exporting them and the other where you’re building your theme and loading them with PHP.
And with the explanation that you’re giving me I think there is a bigger issue.
If I understand correctly you are attempting to load the field group only when a specific template file is loaded for use in showing a page?
This will not work. You need to set the location rules to do this and you need to load the fields when WP is being initialized, not when the template is being used, but I could be misunderstanding what your saying. ACF has ways of adding custom location rules if the ones it has are not sufficient. http://www.advancedcustomfields.com/resources/custom-location-rules/ In order to target a specific landing page template for this plugin you’re probably going to need to create a custom location rule.
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