and just like that, the entire thing cancelled this time. Looks like I might be able to make SFO-ICN-PVG-ICN-SFO work and then buy PVG-XIY-PVG on elong/ctrip. Thanks for the advice.
Never realized that buying a ticket on Star Alliance partners could be so complicated! Used LH, BR, SQ, TG, TK, LX and NH without problems before. Didn't think CA and ZH would be any different!