I was flying from Kunming to Chongqing to Beijing to San Francisco. All on Air China except my flight from Kunming to Chongqing, which was on Sichuan Airlines. Their computer had an error saying my passport number was a mess of symbols, and to call my ticketer to fix it. I was two hours early and my ticketer was open 24/7 so they re-entered the same 'correct' number it in time. Their computer still showed an error.
I had to rebook with another airline to make my next leg, which wasn't cheap. I had no problems with my passport number on Air China. This clearly was their computer's problem communicating with my ticketer's. If you are an international traveler booking on other sites, I do not recommend Sichuan Airlines. Also I can not find a US/English website or phone number for them.