There is a bug with transliteration "on the fly". Let me explain - modern "bt dialer" gadget did not used a request with full synchronization (about 1min) and don't stores contacts in memory constantly.
The gadget makes short request (2 sec) for getting a list of first name + last name each time you enter into a book. And only when you open a particular contact, it loads and show the other fields dynamically.
First quick list (just names) stay on Russian, and only next level (when enter the contact) converted to english.
First level (quick list, russuan letters)
Second level (current contact, right letters)
Parent device Android 5.1.1 (Huawei Honor x2),
Child device Evertones D8\Evertones V5