Assuming that somebody on this forum has seen this phenomenon before and can explain what's happening.

I am booked on tomorrow's LHR-SFO service in WTP, and spotted an opportunity yesterday to upgrade to CW using my points yesterday.

I have just checked in online via mobile app, produced my boarding pass and it says World Traveller Plus on it. The upgrade was definitely effective as I picked an UD CW seat and MMB stated 'CW'.

Is anybody able to explain why the seat says one thing but the text description of my travel class says another? Assuming it's as simple as the BP draws the seat selection separately from the fare class, and the fare class is looking at the underlying fare class of my cash fare?

Anyway I can get it to say CW?!