City names in many cases do not appear at any zoom level. I am seeing this issue particularly in foreign countries, e.g. Russia (Syktyvkar, in the Komi Republic, for example). I have tried multiple label language settings since I am used to reading cyrillic, but no luck.
Also, I am unable to get asian labels to appear in their native languages (chinese, korean, japanese) but only transliterations.
OSM doesn’t have these problems on their web interface, as I can see all of the city names and the native language labels on their website.