Likely the A/C compressor as some previously stated. A mechanic can do a diagnostic to see what is going on. Mine went out at 72K and had to be replaced at the dealer out of warranty, but SoA gave me $400 credit.
CVT has a lag going into reverse/drive. Just remember to stay on the brake when after switching for at least a second before moving.
Don’t listen to all the CVT hate. It’s actually a pretty solid transmission, works well, and shifts fast. Drive modes make it fun as well.
Better than to deal with rev hang, getting gear stuck in 1st gear (TSB on 2015 models, I had this issue in the road twice), and trying to add mods like a short throw shifter and shifter stop to make the shifter actually adequate.
Too bad the current WRX GT costs 45K, but with inflation it is what it is.
