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: 102,617
IMO the upgrade instrument is taken when the ticket is reissued. This can occur at any time after the upgrade is confirmed.
Do you have a new ticket receipt, not itinerary, showing RP class? You normally get an email receipt showing the original coach fare class and then a second email when the ticket is reissued. You can check by clicking "view receipt" at the top of your itinerary on delta.dumb. There should be a new ticket number too.