I don't have a source either, but this has been a concerning trend since around 9/11. First, there is the perception that "things are improving" back in the motherland. The middle class is expanding, and the quality of life is improving. Second, it's hard to get work visas in the US, and there is the perception of hostility towards foreigners (Bush's wars, Trump's election, etc).

The "reverse braindrain" is a serious problem that the US is experiencing in recent years, because the educated foreigners have chosen to get the hell out or have been forced out.

I know a few Chinese with graduate degrees in engineering who are considering returning to China after banking a few more years of American wages. They are heading back to an environmental disaster, but oh well, "progress".

Not an academic source, but... my parents came to the U.S. for graduate school in the late 80's (physics + computer science) and decided to stay and develop their careers here. Literally every one of their classmates (my "aunties" and "uncles") stayed in the U.S.

When I was in grad school from 2005 to 2010, the Chinese grad students (e.g., from China as opposed to Chinese American) were quite diverse in where they were deciding to develop their careers. While some stayed in the U.S., many chose 1) going back to China, 2) academic and industry positions in other places in Asia (e.g., Singapore, Japan, Korea), 3) Canada, Europe, etc.