Catalan as WP Admin Language Leads to Fatal error: Uncaught ValueError

Overview of the issue

If you set your WordPress user profile language to Catalan, you will find this error at the bottom of WPML → Languages page:

Fatal error: Uncaught ValueError: Unknown format specifier “,” in…/wp-content/plugins/sitepress-multilingual-cms/classes/language-switcher/class-wpml-ls-admin-ui.php:593

Stack trace:
#0 …/public_html/wp-content/plugins/sitepress-multilingual-cms/classes/language-switcher/class-wpml-ls-admin-ui.php(593): sprintf()
#1 …/wp-content/plugins/sitepress-multilingual-cms/classes/language-switcher/class-wpml-ls-admin-ui.php(218): WPML_LS_Admin_UI->get_reset_ui_model()
#2 …/public_html/wp-includes/class-wp-hook.php(303): WPML_LS_Admin_UI->after_wpml_love_action()
#3 …/public_html/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters()
#4 …/public_html/wp-includes/plugin.php(470): WP_Hook->do_action()
#5 …/wp-content/plugins/sitepress-multilingual-cms/menu/languages.php(1121): do_action()
#6 …/public_html/wp-admin/admin.php(293): include(‘/mnt/BLOCKSTORA…’)
#7 {main} thrown in …/public_html/wp-content/plugins/sitepress-multilingual-cms/classes/language-switcher/class-wpml-ls-admin-ui.php on line 593

Workaround

As a workaround, you can set a different language for your WordPress user profile.

Alternatively, you can remove or rename the sitepress-ca.mo file in the /wp-content/plugins/sitepress-multilingual-cms/locale/ directory.