Originally Posted by
milepig
Thanks for the background context. Given the situation, I wonder if CTrip actually booked you on two separate itineraries, which would mean that Hainan would have no knowledge of your onward journey when they rebooked you. Just a thought. I know these can pop up as options on some engines, and I quite often see a warning on Google Flights that the option they're offering would be on two itineraries.
Same PNR for both flights. In my experience, Chinese carriers have absolutely horrible IT. The few times I’ve had connecting flights on China Eastern, I was unable to receive boarding passes for both flights at my initial check-in, instead I had to recheck-in at the connecting airport, which is not ideal.