I had this issue as well. It’s making an absolute mess of the PHP error logs.
The issue is that the 2nd parameter passed to path_join is an absolute value and so the path is never actually being joined onto WP_CONTENT_DIR. Calling is_dir on the absolute path: “/plugin-templates/login-with-ajax” is resulting in the warning because on many hosting providers that path will be outside of the webroot.
Current code on line 693: $wp_content_folder = path_join( WP_CONTENT_DIR , "/plugin-templates/login-with-ajax/");
Should be: $wp_content_folder = path_join( WP_CONTENT_DIR , "plugin-templates/login-with-ajax/");
The only change is removing the leading slash in the 2nd parameter.
I fixed this manually on our site, but would love to see this included in a patch version so a plugin update won’t clobber our logs again.
