What I have seen is with the A2A B-17G in joinFS. When the "ATC" box is checked, which is the case if
you want to see other aircraft on your radar gauge or GPS equipped with radar display, you will
]see the '3 intensities' of B-17 landing lights continuously cycling from off to each of the next three
The landing light intensity in the B-17G is normally controlled by the current visibility using one of three different lights. The 'normal' FSX landing light command, the Logo light or one other which I forget at the moment.
That is why hitting the "L" key in a B-17G is a no-no inmultiplayer as it turns on all 3 sets of lights and you look like a miniature sun to other pilots in MP.
Anyhow, this effect in joinFS is annoying but not a show stopped for daytime flying.