Following the upgrade to 3.52 I’m now getting this:
An error of type E_ERROR was caused in line 146 of the file …../wp-content/plugins/nextgen-gallery/src/Functions/deprecated.php. Error message: Uncaught TypeError: Argument 2 passed to C_Lightbox_Library_Manager::register() must be an instance of stdClass, instance of Imagely\NGG\DataTypes\Lightbox given, called in …../wp-content/plugins/nextgen-gallery-pro/modules/nextgen_pro_lightbox/module.nextgen_pro_lightbox.php on line 149 and defined in ……/wp-content/plugins/nextgen-gallery/src/Functions/deprecated.php:146