This mostly happens with a clean install. PR #16978.
@ -1900,7 +1900,7 @@
// Web UI tab
// Language
$('locale_select').setProperty('value', pref.locale);
$('locale_select').setProperty('value', ((pref.locale === "en_US") ? "en" : pref.locale));
$('performanceWarning').setProperty('checked', pref.performance_warning);
// HTTP Server