I had much the same thing earlier today, and it's something I've noticed before. There was a thread where I scanned the car repeatedly for over half an hour and found that the internal temperature dropped every time I scanned it - at first quickly and then more slowly (apart from once giving me that spurious 87C result) until by about 20 minutes it had levelled off a couple of degrees above the external temperature (which never varied, and was correct). The car had been sitting in the garage for about 48 hours at the time, so I'm dubious that the internal temperature was even a degree or two higher than the internal. But that was the result.
Ironically, it's the internal temperature reading or setting that's flaky, while the external temperature is apparently rock-solid reliable. I tend to look at the external temperature in the app, and then make an educated guess at the likely internal temperature, because I'm not scanning it repeatedly for 20 minutes until I get a stable reading!
My car is sitting on the drive. It's been cool and rainy all day. The car hasn't been driven. Around 9 pm when I scanned it, I got 11 degrees external (which it was) and 25 degrees internal (which was highly improbable). I just scanned again and got 10 degrees external and 19 degrees internal. No, I don't believe that. There might have been some solar gain during daylight hours, but it's been dark since about nine, it's been raining all day so everything is wet, and right now, hours after dark, 19 isn't really feasible.
So I refreshed, and got 87 degrees internal and no external reading.
Try again, 17 degrees internal, 10 degrees external.
Next time, 16 degrees internal. It hasn't dropped three degrees in less than five minutes under present conditions.
Basically the internal temperature reading on the app is flaky, variable, and usually higher than reality. The temperature on the HVAC screen has to be set about five degrees higher than the temperature you actually want, in order to get a comfortable cabin.
But the external temperature reading (on the SE as well as the Trophy) is absolutely fine.