I was looking for anyone else with this experience.
My initial impression was that indeed it shows a bit high in cold rooms. I’ve learned this is a very common problem for sensor engineers.
More annoyingly, when restarting it gives a single weird measurement. First it showed high temperatures, now I have a few measurements of -327.7 ℃. There are three reasons I doubt this measurement. It normally only measures full degrees and it is below the absolute freezing point (0 K).