[Resolved] Error code reported from Wordpress and WPML

This was sent to me by the crash detection on WordPress, my site runs but when I visit /wpadmin/index.php I get a message telling me there's been a critical error. When I deactivate WPML, this stops happening.

The error is:

Error Details
=============
An error of type E_ERROR was caused in line 3937 of the file /var/www/wp-content/plugins/sitepress-multilingual-cms/sitepress.class.php. Error message: Uncaught TypeError: Illegal offset type in isset or empty in /var/www/wp-content/plugins/sitepress-multilingual-cms/sitepress.class.php:3937
Stack trace:
#0 /var/www/wp-content/plugins/sitepress-multilingual-cms/classes/translations/class-wpml-post-element.php(54): SitePress->is_display_as_translated_post_type(Object(WP_Error))
#1 /var/www/wp-content/plugins/sitepress-multilingual-cms/classes/url-handling/wpml-url-filters.class.php(445): WPML_Post_Element->is_display_as_translated()
#2 /var/www/wp-content/plugins/sitepress-multilingual-cms/classes/url-handling/wpml-url-filters.class.php(238): WPML_URL_Filters->is_display_as_translated_mode(Object(WPML_Post_Element))
#3 /var/www/wp-includes/class-wp-hook.php(310): WPML_URL_Filters->permalink_filter('hidden link...', Object(WP_Post))
#4 /var/www/wp-includes/plugin.php(205): WP_Hook->apply_filters('hidden link...', Array)
#5 /var/www/wp-includes/link-template.php(371): apply_filters('post_type_link', 'hidden link...', Object(WP_Post), false, false)
#6 /var/www/wp-includes/link-template.php(201): get_post_permalink(Object(WP_Post), false, false)
#7 /var/www/wp-content/plugins/google-site-kit/includes/Core/Assets/Assets.php(1099): get_permalink(Object(WP_Post))
#8 /var/www/wp-content/plugins/google-site-kit/includes/Core/Assets/Assets.php(728): Google\Site_Kit\Core\Assets\Assets->get_product_base_paths()
#9 /var/www/wp-content/plugins/google-site-kit/includes/Core/Assets/Assets.php(357): Google\Site_Kit\Core\Assets\Assets->get_inline_base_data()
#10 [internal function]: Google\Site_Kit\Core\Assets\Assets->Google\Site_Kit\Core\Assets\{closure}('googlesitekit-b...')
#11 /var/www/wp-content/plugins/google-site-kit/includes/Core/Assets/Script_Data.php(51): call_user_func(Object(Closure), 'googlesitekit-b...')
#12 [internal function]: Google\Site_Kit\Core\Assets\Script_Data->Google\Site_Kit\Core\Assets\{closure}('googlesitekit-b...')
#13 /var/www/wp-content/plugins/google-site-kit/includes/Core/Assets/Asset.php(129): call_user_func(Object(Closure), 'googlesitekit-b...')
#14 /var/www/wp-content/plugins/google-site-kit/includes/Core/Assets/Assets.php(1017): Google\Site_Kit\Core\Assets\Asset->before_print()
#15 /var/www/wp-content/plugins/google-site-kit/includes/Core/Assets/Assets.php(1026): Google\Site_Kit\Core\Assets\Assets->run_before_print_callbacks(Object(WP_Scripts), Array)
#16 /var/www/wp-content/plugins/google-site-kit/includes/Core/Assets/Assets.php(1026): Google\Site_Kit\Core\Assets\Assets->run_before_print_callbacks(Object(WP_Scripts), Array)
#17 /var/www/wp-content/plugins/google-site-kit/includes/Core/Assets/Assets.php(1026): Google\Site_Kit\Core\Assets\Assets->run_before_print_callbacks(Object(WP_Scripts), Array)
#18 /var/www/wp-content/plugins/google-site-kit/includes/Core/Assets/Assets.php(156): Google\Site_Kit\Core\Assets\Assets->run_before_print_callbacks(Object(WP_Scripts), Array)
#19 /var/www/wp-includes/class-wp-hook.php(308): Google\Site_Kit\Core\Assets\Assets->Google\Site_Kit\Core\Assets\{closure}('')
#20 /var/www/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array)
#21 /var/www/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#22 /var/www/wp-admin/admin-header.php(146): do_action('admin_print_scr...')
#23 /var/www/wp-admin/index.php(137): require_once('/var/www/wp-adm...')
#24 {main}
thrown