Blizzard said that it does not work right. I tried this on Test realms. And it does not work if u have Enduring Winter talent. If u don't chose that talent, it work's good. And i did write ticket to Blizzard about that. I guess that they didn't pay to much atention to it. True, i did not tried this on Live servers.
I did not make this topic for discussion. It is more like advice if u want to try Frost as PvE. Just don't put any talent point to Enduring Winter, and it'll be fine.