Zigbee2MQTT Zigbee group is controlling devices outside the group

I have many devices, but these are the related ones;

  • zigbee_1 (in the zigbee2mqtt group zigbee_group_vindfang_taklamper)
  • zigbee_2 (in the zigbee2mqtt group zigbee_group_vindfang_taklamper)
  • zigbee_30 (in no group)

When I control zigbee_1, only zigbee_1 change
When I control zigbee_2, only zigbee_1 change
When I control zigbee_30, only zigbee_1 change
When I control zigbee_group_vindfang_taklamper, all of the above is changing, none else.

Is this a bug, or what? I dont have any automation controlling this,