I am starting to conclude this is a temperature issue. I met someone else that had this issue, and was told the first level of high (oil) temp is short shifting. He then got the oil temp as high as 300 and saw an alert pop up on his dashboard to back down. He said third radiator solved the issue.
I tried various “home remedies” and took the car out again. This included brake flush (since the dealer thought it had something to do with brake fluid temp), running Techron in my gas, and having my radiators cleaned out. None of this worked. I then started looking at what my oil temp on the dash was immediately after this occurred. It appears as if this first stage limp mode kicked in when oil temps hit 280+. It didn’t seem to go away until it fell below a certain threshold (might have been sub 260 or so). One way to get the car going again is just to drive the car at lower revs for a bit, then get back on it. Also, cool down laps are now being done at about 4K rpm and leaving car running when I get to paddock until oil temps hit sub250. Apparently 981 engines run a lot hotter than 987’s.
Ordering a third radiator soon and will test out in two weeks and report back.