Wierd behaviour of ITC-100RH when changing SV

Hi! I’ve been having a strange behaviour in the controler when changing the SV.
When I try to change the SV, the PV changes. For example:
SV is in 1°C
PV is in 1.2°C
I change de sv to lets say, 0,5°C
The PV suddenly changes to 3°C
If I turn off the controler and on again this “fixes” back to 1,2

Here is a video of whats happening

is this supposed to happen?

May I know what type of probe are you using?
What device is connected? What is its power and voltage?

we are using a pt100 probe. It is connected to a fermentation vessel in a brewery-
It is connected to 220v


May I know what is the power (watts) of the heater?
According to the video, the OUT indicator of ITC-100RH is on, indicating that it is in the output state. There may be temperature fluctuations at this time. Temperature fluctuations are affected by the power of the heater.
In addition, please make sure that the PT100 wiring is correct. Please refer to:

Hi thanks for your reply, after a lot of work, the complex problem was because of a very simple matter…the conexion was not tight enogh, yes, the screws were a little bit loose. Thanks!!!