GD Content Tools Pro 5.3 branch has been updated to 5.3.7 version. Over the past few months, the plugin has been updated several times to fix various issues, add some minor new features and various improvements.
Over the past 6 months, the plugin has seen 7 minor updates, fixing 15+ bugs, adding few minor features, and improving existing features. Most of the bugs were related to the meta boxes and custom rewrite rules for post types. It is highly recommended to update the plugin to this latest version, and avoid few recently discovered bugs. Check out the plugin changelog for the detailed list of changes.
Next major 5.4 version is now scheduled for late September, and you can expect new meta field types, some meta enhancements including replacing the current date time picker due to the various issues it caused, and the fact that is no longer in development. Depending on the progress of Gutenberg integration into WordPress, new plugin version will include some Gutenberg related updates too.
If you notice any more issues, please report them in the support forum.