KNX Integration does what it wants :(

This seems like you are creating loops.
If this light isn’t controlled by a Knx actuator, then do not create a Knx light entity for it.
Instead have a look at Advanced control of any light entity from KNX (state, brightness, dim, temperature, color + states feedback)
or maybe https://youtu.be/O3p3dISvTtI to set up an Automation.