United couldn't see the same P space on AC that Google Flights did. I needed UA ticket stock for RDM and PQM earnings. The OTAs through Google Flights would only plate it on LH ticket stock and Priceline through BookWithMatrix would choke because of the last YVR-SFO leg - it was fine if I just terminated at YVR. I finally got it ticketed through Propeller Travel which others have recommended here for complex ITA itineraries which you can't get ticketed through other channels. Fortunately for me (or my employer), the fare actually went down by $2k or something in this whole process.