UPG code in boarding pass?
 

Hi there,
I'm flying ARN-MAD in economy and my boarding pass includes fast track and a UPG code which I had never seen. It's quite strange since I'm only a silver member and that doesn't entitle me to fast track at MAD. Maybe it is related to the fact that this flight is the one where I achieve my gold status. Any info on this UPG code or the fast track?

Thanks!

Did you bid for an upgrade?

No, I didn't. The inward flight in the same booking is in J though, and the boarding pass has the same UPG code.

Fast track did appear to me in a couple of times, flying YW while I was OWR with BA. I guess it was a glitch of the system.

If you have been upgraded, why is your seat in the economy section??

Thanks for your answer. This is what is bugging me, I haven't been upgraded, but this upg code shows up in my boarding pass...