Originally Posted by
Meerkat
Not much succour to the OP, but I've been op-upped from Y to F before.

Interesting to know that it did happen on CX. CX normal way is to op-up a Y (redemption or revenue) passenger to J and a J (redemption, upgrade or JCDI) passenger to F.
Even if it happened before, it is, in general, not expected even on a full Y and full J flight.