Haali said there is an overall limit of six months in any two year period. What's the source for that?

I was talking about the standard tourist visa that Brits can get for China. I know about it because my father, mother and sister all currently have this visa. I don't know what visa the OP has but if it's the tourist visa then it cannot be used for a long term stay.

So the source is a talk with your family?

I leave every 90 days and have rented long term with no problems, so shouldn't affect how the psb views your lease. But I have a US tourist visa, just a caveat, so don't assume it's exactly the same in your case, sorry about the long qualification, but I don't want any grief from the poster Napoleon about Americans offering their experiences.

I also think that the issue is not with PSB (and definitely not with landlord), but MAYBE with immigration control.

As in border control, getting in and out.