use load_plugin_textdomain instead of translation load_textdomain. this would have wordpress handle translations and translation overloading and would allow the usage of plugins like loco translate. more info here https://developer.wordpress.org/reference/functions/load_plugin_textdomain/ and here /// load_plugin_textdomain() will try to load the mo file firstly from: WP_LANG_DIR . ‘/plugins/’ . $mofile. more info in ticket #235713