Thanks for your reply.

This is certainly very strange. The first screenshot does show the fare class selection panel being different from what I'm used to.

I recall that CX progressively rolled out new booking system. There were sightings happening in the Australian market. I'm not very sure it applies to Doha too.

But this is wrong of them to have allowed this to happen. You paid well above premium economy standard ticket to have the full flexible fare, and yet was booked into M.

Call CX and let us know.