WP 4.7 will be introducing page templates for custom “Posts” and custom post types into core. There have been changes made to incorporate this new that is being added to WP Core. I’m not sure what plugin you’re currently using to select page templates for custom post types, but the change in ACF has probably affected the operation of that plugin. See this post on the new feature in WP https://make.wordpress.org/core/2016/11/03/post-type-templates-in-4-7/. It could be that you just need to add the “Template Post Type:” line to your templates, but I’m not sure it will correct the problem with the other plugin or not. It seems that the change in WP will have a significant impact on the plugin that you’re using.
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