I have the same issue on an upcoming trip. 23 sectors on QF, JL, CX, AA, BA and AY. I'm QFF Silver (OW Ruby) now. I'll earn Gold (Sapphire) on the 5th sector. My member year ends while I'm away (after another 2 sectors after earning Gold). I'll earn Platinum (Emerald) off the last sector.
I'll be travelling while my new gold card is sitting in the mail at home. Will any of the airlines have issues with my having a Ruby card and a Sapphire boarding pass? It is a Business class ticket.