As it seems the OP is content, I'm locking this thread.
Clearly there is an issue with this machine, or at least its headstock, but not one that would be obvious under a normal inspection (which wouldn't involve taking the headstock off).
It is a shame if people get the impression that all imported machines are likely to have issues of this kind. The great majority don't, but unsurprisingly people are more likely to post when they have a problem, than when they do.
Neil