EU 3Phase reversed icon

I have done 2 installations for homes in EU 3phase. The first one went smoothly.
The second one I keep getting this reversed icon next to some inputs. We have triple checked that A is A then checked all the sensors directions K-L is correct and all matching each other. Then switched B with C as last desperate measure, but the numbers started to make less sense, so I put them back. I also noticed that the reversed icon comes and goes depending on the how high the load is.
What is the logic of the reversed icon? If I am sure that we have installed everything correctly do I need to worry about it? I know that in the 3-phase systems it is very important to have the direction correct and I did emphasis that to the electrician and he confirmed. So I am a bit lost now.

I have my third installation coming and would like to know more about this.

Are these 3 wire or 4 wire systems? Could you post a high resolution picture of the breaker panel?

I have also done some three-phase installations and partly made the same observation. The reason is the polarization of the socket, so on which side is the hot wire and on which side is the neutral conductor. You can fix this by plugging the power supply into the socket the other way round, which is usually not very nice. But the polarity can also be changed in the IoTaWatt in the voltage reference configuration menu: