she may have never really worked in a company in the US. Even at a none-managerial level, most of the staffs would know how to deal with other people in a flexible and self-protective manner.
This person may have only gone to school in the US and read too much bull-shit from the Chinese "People's Daily" glorifying Chinese Returnees.
If she works in my place, I wouldn't wait that long to fire her, no matter in China or anywhere. She could only do damage, no value added.