[Ammako]

This is what Blizzard uses fwiw

function CompactUnitFrame_UpdateInRange(frame)
  if ( not frame.optionTable.fadeOutOfRange ) then
    return;
  end
 
  local inRange, checkedRange = UnitInRange(frame.displayedUnit);
  if ( checkedRange and not inRange ) then  --If we weren't able to check the range for some reason, we'll just treat them as in-range (for example, enemy units)
    frame:SetAlpha(0.55);
  else
    frame:SetAlpha(1);
  end
end

https://www.townlong-yak.com/framexm...tFrame.lua#648

frame.background doesn't seem to be a thing here, not sure where you got that code from but it could have been from an older version of the game and raid frames may have changed since, idk.

You can always override this by doing something like this:

hooksecurefunc("CompactUnitFrame_UpdateInRange", function(frame)
  if ( not frame.optionTable.fadeOutOfRange ) then
    return;
  end
 
  local inRange, checkedRange = UnitInRange(frame.displayedUnit);
  if ( checkedRange and not inRange ) then  --If we weren't able to check the range for some reason, we'll just treat them as in-range (for example, enemy units)
    frame:SetAlpha(0.3);
  else
    frame:SetAlpha(1);
  end
end)