When Matched Downlink Loss mode is selected, VR5 will set attenuator to the minimum RF path loss among all the RF channels
Even if you disable RF output port from RF Grid, the path loss will be also set accordingly,
To avoid this, you may need to disable all the radio links related to that path, for example, if you want to disable only port B1/B2, you will disable all of the 4 paths for this setup like below: