Talk page mentions an "exception" where the Czech Republic told the UN its short name was Czechia in 2016, but its name plate was not updated until 2022. This sounds right by my recollection, but I can't find a source on the date other than the ECOSOC membership page, where the Czech Republic was elected to a 3-year term starting Jan 2022 and its name in the membership list has changed to Czechia by Jan 2023 (en)