[Koha] problems with browsing

Dear friends, We have upgraded to koha 3.8 and are currently testing it. Till now everything has worked fine with one exception. When we import a MARC record in Armenian language and search for it, the record is normally retrieved. But when we try  to browse by author/subject/etc by clicking on the author/subject name-link, some strange things happen. Obviously, koha dos not recognize the fonts. Koha uses strange symbols to search/browse the author name. In the koha 3.6 we have not encountered such a problem. Any ideas? Regards,  Haik.