Internal thermometer on the oven - sous vide vs regular mode

I cooked a pork tenderloin and then tried to cook asparagus right after. I needed to raise the temperature from 147 to 185. In sous vide mode, this was excruciatingly slow. After 30 min, I changed the oven to regular mode, to see if it would heat faster.

In sous vide the internal temperature was about 175, once I changed to regular mode it was reading around 205. The temerature started dropping towards 185. I swapped back to sous vide, and the temperature was lower, say 172. It started heating again.

I repeated this several times. Each time the regular mode oven showed a higher temperature and started to lower the temperature, and sous vide mode showed a lower temperature and started heating again.

Why is that?

Sous vide mode compensates for evaporative cooling as measured by the wet bulb sensor.

edit: add video

Check this good video out with Scott from Anova

The oven was empty . Where would evaporative cooling come from? both recipes were sous vide mode, at 100% humidity

The steam.