I can confirm the same issue. After the plugin has been updated today, we are getting:
Warning: Undefined array key “fancybox” in /data/web/virtuals/virtual/www/wp-content/plugins/responsive-lightbox/includes/class-frontend.php on line 862
Warning: Undefined array key “fancybox” in /data/web/virtuals/virtual/www/wp-content/plugins/responsive-lightbox/includes/class-frontend.php on line 865
Warning: Trying to access array offset on value of type null in /data/web/virtuals/virtual/www/wp-content/plugins/responsive-lightbox/includes/class-frontend.php on line 865
Warning: Undefined array key “fancybox” in /data/web/virtuals/virtual/www/wp-content/plugins/responsive-lightbox/includes/class-frontend.php on line 862
Warning: Undefined array key “fancybox” in /data/web/virtuals/virtual/www/wp-content/plugins/responsive-lightbox/includes/class-frontend.php on line 865
Warning: Trying to access array offset on value of type null in /data/web/virtuals/virtual/www/wp-content/plugins/responsive-lightbox/includes/class-frontend.php on line 865
Warning: Undefined array key “fancybox” in /data/web/virtuals/virtual/www/wp-content/plugins/responsive-lightbox/includes/class-frontend.php on line 85
Warning: Undefined array key “fancybox” in /data/web/virtuals/virtual/www/wp-content/plugins/responsive-lightbox/includes/class-frontend.php on line 88
Warning: Trying to access array offset on value of type null in /data/web/virtuals/virtual/www/wp-content/plugins/responsive-lightbox/includes/class-frontend.php on line 88
Fixed by re-saving the Responsive lightbox plugin configuration.
