There is a lot of speculation regarding the fuel uplifted in PEK. BA38 would probably have uplifted it's fuel from the hydrant system at terminal 2. PEK shifts a lot of fuel, it nearly has as many movements as JFK these days. A lot of other aircraft would have also uplifted fuel from the same system, including the 8 flights my company operates each day to PEK. There are no reports of other problems, and my company is not concerned about substandard fuel at PEK.
Regarding cold soak, it may be significant that while the aircraft was on the ground at PEK, the temperatures were sub zero. This means the aicraft would have been cold soaked for a period in excess of 24 hours.
One thing that is not always known is that jet fuel supplied in China is not always Jet A or Jet A1. It's known as RP-3 (or No. 3 Jet Fuel) and is compatiable and aligned with Jet A1. It has a freezing point 2 degrees lower than Jet A1.