Originally Posted by NickB
This is because GDS are not good at dealing with carrier-specific booking classes. They recognise C, D and J as business class or F, A and P as 1st class booking codes are these are widely used. Others are normally assumed to be discount economy codes by the GDS even if the airline's own reservation system knows better.
Thanks, a very good point, I hadn't thought of that.

In fact, for the trip in question that I mentioned above, one leg was in award First (AF code "A") and it, indeed, showed up fine on checkmytrip.com