failing test when asking a key in a language with a different plural form

Seems that is ignoring any plural form even if it comes from a language that has a plural system that is different
i18n.setLng("en"); //object
i18n.t("date.day",{count:2}) // Days
i18n.setLng("zh") //obeject
i18n.t("date.day",{count:2}) // 日
i18n.t("date.day",{count:2, lng:"en"}) // Day
i18n.setLng("ar") //object
i18n.t("date.day",{count:2, lng:"da"}) //Dag //wrong
i18n.t("date.day",{count:2, lng:"en"}) //Day
i18n.setLng("en") //object
i18n.t("date.day",{count:2, lng:"da"}) //Dage //correct