Temp increase ewilink / Sonoff is off….!

I own a Sonoff TH-16 Elite with the ewilink apps. I’m trying to understand why the temperature of my pool increases in temperature in the ewilink application while my pool heat pump is closed Off??
Exemple: this morning the pool temp is 84F and my ewilink app say 91.4F
Any ideas is appreciated

Your pool temp in this morning is 84F. May I know how do you get this temp? Does it show on the TH Elite’s screen? Or another smart device detected the pool temp to be 84F?

From pool thermometer attach on ladder

Is the temp showing on this pool thermometer always correct? In fact, the TH Elite detects your pool temp first, then it sends the value to our server, and finally, you can view the temp on the eWeLink App. If you have any questions on the TH detection accuracy, please feel free to reach out to the manufacturer.