Post History

This is not something unique to Chinese, it is most commonly seen with British speakers: https://languages.codidact.com/posts/288307

The Chinese were historically much more exposed to British, in particular to upper-class British English. I suspect that a legacy of that is taking up some of their phonological habits. English instruction in China, like many other countries, probably uses https://en.wikipedia.org/wiki/Received_Pronunciation as a basis since that's often taken as "the" English.