Rukovoditel Support Forum

Yes, there's another filter customer that works just fine.
It has the same field type Entity.

I just found out that in Merk Field, I can only filter 1 choice.

Hard to say what is it. I can't reproduce it. Try to do more test maybe you can find some relationship why it happens.

For example create new Entity just for testing and paly with this filter.

Also try to reproduce similar issue on personal demo https://www.rukovoditel.net/demo.php