It's my opinion there are generally 4 kinds of Chinese UHNWIs:

1. Mainland with no interest in foreign investment

2. Mainland mostly with some foreign investments

3. Split between mainland and foreign

4. Trying to move mostly foreign while keeping some in mainland (generally to take care of family or business concerns back home)

In the US as a more stable asset haven, hot real estate markets are usually where large piles of cash are parked by global investors, not just Chinese. The people in the 4th group often try to emigrate because individual property rights still aren't fully guaranteed in China. (Jack Ma is an example.) You would too if your neighbor had their assets seized or frozen arbitrarily.