I don't think anything caused it. We only have reports to go on. Other people in proximity who should have also been affected weren't. I think it's made up.

Here's the problem with "energy weapons." They're not kinetic. So you can literally just reflect them with either shaped material or special paints. The power falls of with the square of distance. They get exponentially weaker due to spreading the further away you get and they experience linear spreading of effects reducing your ability to target them accurately. They require absurd input voltages, which means direct grid tie, or a massive whacking transformer which gets hot under load.

They're just not practical as targeted weapons. The most you can get out of them is area denial in asymmetric conditions. If the opposing force can target the generator they will immediately. Same reason anti air missile sites are separate from their radars or don't turn the radars on until just before firing.

There are so many better ways to target an individual and with better effect than "occasionally gets headaches and hears ringing in their ears."