Nikon F4 Focus confirmation

Is it normal to have a Nikon F4 that is unable to focus confirm with manual glass 50 percent of the time? It seems to toggle between the red "X" and the red arrows a lot, depending on the scene.

Is there something wrong with my camera or is this normal behavior?

Mine does the same, once I get the flicker between the two arrows I feel that I am close enough, unless shooting wide open with a 50 1.4 at 1.4 then I take the extra time to get the green LED to stay put.