After some research on the Company side I found something interesting.
They wrote to try the following to adjust the temp. :
The E Heater is very visual, and is showing you in detail what is happening in the tank. You are seeing changes that you would not likely see with a heater that simply has an on/off indicator light.
Your E heater may have needed to be reset, to do this turn off the heater and re-position the heater on a 45 degree angle, then turn on the heater and turn down the temp as low as it will go, 18 degree’s, then turn up the heater as high as it will go, 34 degree’s, after this set the heater to the desired temp and leave at a 45 degree angle.
You may find it helps if the heater is positioned on a 45 degree angle to disperse the heat .The heater is so sensitive, it may read the water temp inside the heater guard if positioned vertically and if the water circulation around the heater is compromised in any way.
I tried that and since then I have no problems anymore. I have it hanging in a 45 degree angle now on the right side close to the front.
No more LF and no more blue.
Fingers crossed that it will be the same tomorrow morning