This issue should be resolved in the latest 6.5 release of ConnectWise Control.
I was able to reproduce this behavior in our development environment by installing Control on a Windows server with Russian as the primary language. It looks like Cyrillic characters aren't written properly to the database when the server processes the session connection event, e.g. "контроль" is written as "Є®ва®«м"
While I'm unable to offer an ETA for a fix, I have registered an issue with development.
Customer support service by UserEcho