I was also affected by this, unfortunately flying on a China Eastern ticket, LHR-FCO-PVG. Check-in lady said that it my bag should get on the flight to Rome as there still remained 90 mins before departure. No bag on arrival in PVG, and filed a claim with China Eastern at Shanghai - it all seemed very perfunctory and I had kind of resigned myself to never seeing the bag again. Headed to a small provincial city, and have managed to get some basic items. I tried to log the missing bag on the BA website, and let me enter lots of lovely details all the way to the end, but it reported an error at the end, presumably as it was not a BA ticket.

Sunday I got an email from China Eastern, obviously written by a human, advising the bag should arrive in PVG today (Monday), so a 2 day delay at LHR. They have offered to forward the case to this small provincial city, so all-in-all, not a terrible result. I will claim with travel insurance, presume no chance of reimbursement from BA. I did take a photo of the bag as I left it outside check-in at the BA Club section, which the China Eastern rep took a photo of on his phone.