That barely makes any sense if Jumbo says they have planned going to the Vuelta since November. I can't imagine that you're planning that without glancing at the route beforehand.. because Vingegaard seems like a guy who's pretty interested in that stuff since race routes are very important for his chances of winning compared to other riders IMO.
Then again, maybe he's just been 100% focused on TdF without given a single *** or thought about La Vuelta and is just full blown yolo'ing it for *** and giggles. No altitude, no recon, no nothing.
There's an abyss between his TdF level and being competitive at Vuelta level. Maybe they hope he'll still be decent enough and able to fight for top3 (plus it's maybe a trial before future double attempts).