Yes, I agree this should not be a very serious problem, but

I think good reason means the reason you reported to your university or the place you work when you first left China. Like, if you go abroad to study, normally you would specify how long it will take. Within that period, that is a good reason, but what about after that? Did you report the reason why you did not go back after your study? If not, then that is not a good reason.