Cyrillic names stay broken until reinsert the microSD card

[ktulx]

Hi.
I'm experiencing some very odd and tedious issue with cyrillic file/folder names.
The device is Samsung YP-R0 with Rockbox b130b50-150329 and 64Gb Kingston microSD card.

When I turn the device on and go to the microSD, all the cyrillic filenames appear as ? ? ? ? ? ? ? ? ? ?.
Then I take off and insert the card again - everything is perfect.
The problem is related only to microSD. The internal memory doesn't have this behavior.

What can it be?

Thanks.