dont know if this fits this exactly - but im traveling SFO - EWR this week and they swapped the 77w (or 78x) i cant remember to an awful 767-400er.

I paid for Prem Plus and when the equip got swapped i got downgraded to Econ+ since there is no PP product on that bird.

I had to call in and get my refund/adjustment, but had to do it manually.

Maybe the system is buggy on a Sunday because when I went to do a dummy booking, it still showed a 77w with Pp being sold even though i know for sure its a767-400er with no PP