As titled, the majority of ground vehicles with spotlight functionality cannot turn them on.
There is no option in the context menu to turn them on, as there should be.
Driving the vehicle to a repair station does nothing, nor repairing via master arm.

This appears to apply only to vehicles that are spawned in using mike forces respawning vehicles - which never work, as the exceptions to this are vehicles spawned in via the editor, or via Zeus, where their spotlight functions work normally, and the spotlight options appear in the context menu as they should. Hence the reproducibility set to sometimes

I have tested this on various community servers and the official mike force servers, and was able, with help from whiplash, to confirm that vehicles that were spawned via Zeus do have the correct options and functionality, whereas the vehicles that were already in the ACAV base, none had functional spotlights.

As previously stated this applies to most ground vehicles, i have not tested them all personally as some do not appear in MP servers, and i could not get this bug to occur via my own editor testing, But i can confirm it happens on at least most M113 crew served weapons, M67 zippo and the M48 Patton.

It is hard to get screenshots showing this for an explanation but i have tried,
Please see attached screenshot showing Patton tank with drivers headlights on, Turret rotated slightly to show separate light sources. Note lack of spotlight option in context menu, but please also note the strange ghost spotlight cone, as if the spotlight should be on but is not producing any light, nor can it be interacted with, this ghost cone is always present in the bugged vehicles.