A FlyerTalk Posting Legend
Join Date: Sep 2009
Location: Minneapolis: DL DM charter 2.3MM
Programs: A3*Gold, SPG Plat, HyattDiamond, MarriottPP, LHW exAccess, ICI, Raffles Amb, NW PE MM, TWA Gold MM
Posts: 100,399
My guess is that when you used the GUC to upgrade, the flight was rebooked into O class, which normally is ("free") award inventory class on KE. This causes DL's computers to see it as an award ticket, rather than an expensive coach ticket that was upgraded. You should be able to get correct credit for the flight, but it might require some persistence.