Freeradius, PPPoE and non latin characters

Hello, I have installed freeradius at linux box and connected Mikrotik with v6.37.5. On Mikrotik i have PPPoE server which using that radius and everything is okay when i’m testing with passwords containing only latin characters, but when I’m trying to login using password “łał”, there is error saying that is wrong password. I have tested that account using radtest tool and it work.
I have sniffed communication between radius and mikrotik/radtest and i see that password is different:

Radtest → Radius packet fragment:

AVP: l=18 t=User-Password(2): Decrypted: \305\202a\305\202

Mikrotik → Radius packet fragment:

AVP: l=18 t=User-Password(2): Decrypted: \263a\263

How can I fix it? Can I or its bug?