URL

https://www.openstreetmap.org/#map=13/51.16696/14.45114&layers=V

How to reproduce the issue?

Select "hornjoserbsce" (Upper Sorbian) in the language menu and zoom into Lusatia (see URL above). Labels are not "name:hsb" but simply "name". After a quick research that seems to be a problem with all three-letter ISO codes (try for example sicilianu).

Screenshot(s) or anything else?

No response