Random text pastes all of the sudden

I was working on my illustration when all of the sudden some random text popped out as pasted text. It happens again and again usually when I hit option key, X + shift while using pen tool. I think there's something with shortcut settings. Can anyone tell me what's going now? Thank you!!!

P.S. letters are Russian but they make no sense at all. It looks like a web code or some sort.