I think what might be happening here is that in the c++ we use std::endl to finish writing where we may just want to append a \n to the string we want to log.
The way we do it right now is something like
stream << msg << std::endl;
If your not familiar with c++ the operator << is normally used to pass a message to a stream. The message being sent in one operation and the end line being sent in another is most likely causing the overlap you are seeing here.
I’d classify this as a bug and think we should just send append a \n to each message we send to the logger so we don’t have this line overlap. The new code could just be something like
stream << (msg + "\n");