I have a guess.
It is maybe due to the heat inside the box that disturb something.
At 12:00 today the exhaust indicate 35.6° aand the ambient temp was 30°
At 08:30 the ambient temp was escalating from 30 to 34°that mean at that time the exhaust air from the board might have be 40°
I decide to move the A3 to a new location from screwed to the inside part of the wooden shutter to a cool wall.
Will see

Hi

Thanks to you to for helping
Have a great day.

Cheers
Yves

Everything works fein
The two pic below represent the graphs of the day for my two outside unit rads and temp

I apply the heat exactly where Radu point on the picture he submit.
By the way, the black wire that was cut maybe also the cause.
I couldnt say if it was cut before or after the opening of the casing.

Thank you all,

As my A3 was pen board and one of the wire that rely the sensor to the board was cut.
After re-solder I pass a 300° rework air blow lightly on the card specially in the middle under the Geiger tube.
Since, it seems to rework.

Crossing the finger 🙂

Thank you for the tip Wolferl.
I will try that and keep you informed.
And sorry for the wrng link

My box router config is from 192.168.0.10 to 192.168.0.50 address range.