Family and I were flying on F tix from NYC to SGN (we were on mix of revenue tix, Asiamiles award and J cash+ DM upgrade).

The HKG to SGN leg was on a 77W with F. Every other time in last few years (50+ instances) this route was been served with an F cabin and i was in J, they seated me in F. Their system is smart enough to know i like 2A

They sat the three of us in J on HKG to SGN. I was irked they didn't seat us in F, considering we all had longhaul F tix. The response from the crew - "oh we never set DM members in F on this route unless J is full" 10 seconds before someone sat in 1A, lol, - just irritated me further.

I complained a bit about the 'fake news' response, and the gate agent came back new boarding passes in the F seats, which I declined on the basis that I don't want to beg our way into a higher cabin. My gripe was much less about sitting in 1k / 2k vs 11k and 12k for a short flight, and more about CX getting customer relations wrong (from my POV).

Interested in other views.