Minus sign removed between temperatures -0,1°C and -0,9°C

[S0lmyr]

Hi, it somehow removes minus sign from temperatures between -0,1°C and -0,9°C?

You can see in the graph (upper), that the temperature is going down. When the temperature reaches -0,1 °C it actually sends +0,1 °C, -0,2 °C sends + 0,2 °C , etc... up to -0,9 °C.. The temperature -1°C is ok.