MDT Weather station

I’m using a MDT Weather station to track brightness, windspeed and temperature.

In order to create a smart system to reduce the sunlight / heat that gets into our house (controlling blinds e.g.) i took a look at the brightness sensors which showed some strange behavior.

As you can see in the picture all sensors (east, south, west) raise almost at the same time.
While the east sensor has a maximum at about 9 am both south and west go down again, stay at a certain value and raise when the sun i coming from south/west respectively.

The resulting difference in their maximum value is expected, that “base level” of illumination also (scattered light?!), but why do they raise and go down again?

There is nothing blocking the sensors, nor i see any reflection sources.

Any ideas? What do your sensors show?

I installed the MDT Weather Station 3 days ago and need to take a closer look to the results, but if it helps please find attached my results