When sending Cyrillic characters in the user properties, the characters lose their encoding and turn into incomprehensible characters.
I use HTTP API V2 on Windows
String “Отважный тигр” becomes in ÐÑважнÑй ÐÑÑл
At the same time, there is no such problem with Latin characters and numbers.
There is also no problem when sending Cyrillic through Unity SDK on Android and iOS