Siwarex U problem

I have a Siwarex U one channel with 3 RN load cells , my problem is that the reading is shifting slowly , it increases or decreases 0.1 KG and keeps going . But the difference reaches around 10KG . The ambient temperature is around 6 celcius , but when I run the process the tempoerature of the machine that is on the load cell becomes around 13 so its around 7 degrees difference , could it be the reason or can you think of something else ?

Thank you