Issue with Types and WordPress Menus

Symptoms

When adding a menu item for a custom post type archive, there can be unexpected and different errors depending on your WordPress version.

Explanation: our implementation of custom post type archive items in the navigation menus was based on WordPress API which is a progress in work and is still being worked on. This has resulted in a feature that is difficult to mantain and which might have some incompatibility degree with certain WordPress versions. At the moment, the functionality kind-of works, but might be buggy and will be deprecated.

Workaround

WordPress 4.4 will provide this same functionality in a native way, and we will stop providing our own implementation as soon as the site gets updated. After that, you might need to add your custom post type archive menu items again to make them 100% compatible.