On Page Save we got a 502 and it looks like the cause is WPML:
Howdy!
Since WordPress 5.2 there is a built-in feature that detects when a plugin or theme causes a fatal error on your site, and notifies you with this automated email.
In this case, WordPress caught an error with one of your plugins, WPML Multilingual CMS.
Error Details ============= An error of type E_ERROR was caused in line 143 of the file
/var/www/html/wp-content/plugins/sitepress-multilingual-cms/menu/post-menus/post-edit-screen/wpml-meta-boxes-post-edit-html.class.php.
Error message: Uncaught Error: Cannot use object of type WP_Error as array in
/var/www/html/wp-content/plugins/sitepress-multilingual-cms/menu/post-menus/post-edit-screen/wpml-meta-boxes-post-edit-html.class.php:143
Stack trace: #0
/var/www/html/wp-content/plugins/sitepress-multilingual-cms/menu/post-menus/post-edit-screen/wpml-meta-boxes-post-edit-html.class.php(57):
WPML_Meta_Boxes_Post_Edit_HTML->translation_priority() #1
/var/www/html/wp-content/plugins/sitepress-multilingual-cms/sitepress.class.php(1974):
WPML_Meta_Boxes_Post_Edit_HTML->render_languages(Object(WP_Post)) #2 /var/www/html/wp-admin/includes/template.php(1304):
SitePress->meta_box(Object(WP_Post), Array) #3 /var/www/html/wp-admin/edit-form-advanced.php(635):
do_meta_boxes(Object(WP_Screen), ‘side’, Object(WP_Post)) #4 /var/www/html/wp-admin/post.php(197):
include('/var/www/html/w…') #5 {main}
thrown
I have reverted back to our last version which is 4.2.4.1 which is working without any issues.