"This hyper-correction of speech is a sign of a class divided against itself, whose members are seeking, at the cost of constant anxiety, to produce linguistic expressions which bear the mark of a habitus other than their own."
- Pierre Bourdieu
Of course ironically hypercorrection marks you as the very thing you probably do not wish to be. I don't really like applying this to Chinese English because it's so influenced by the idea of social class, and I don't want to promote the idea of a linguistic hierarchy -- although there probably totally is one, and in terms of the popular imagination of English-speaking people, China is pretty low on the English totem pole, despite statistics (take this clever but ultimately insulting fake Chinglish article in the Telegraph, for example).
But there may be something to it. Chinese English teachers seem to follow 'the rules' (whatever they are, and the source of 'the rules' is interesting and not at all clear to me) of English usage more assiduously than native speaker teachers, especially when it comes to "the small words" -- prepositions especially. It's a kind of paradox -- preposition errors are one of the most obvious markers of non-native speaker status, yet concern with preposition errors is one of the most notable differences between native and non-native speaking teachers. (At least anecdotally as I'm going through my notes.)
In fact it probably isn't the Chinese teachers who are overcorrecting so much as the NESTs are undercorrecting -- but that's the privilege of the NS. You're allowed to not care as much about 'the rules' if you have enough cultural/linguistic capital in the eyes of the (imagined?) custodians of the rules.