No specialist about the Whole details, how a sensor works, but i think crazy bright Flashes like those that get generated when filming arcs can not only seriously Mess with the Way the sensor works (If you throw enough Light at electronic Sensors, like those that sense the Brightness in the Imaging Sensor of the Camera, at some point they start to do things they are not supposed to do, like Loose data or generate funky images), but also actually damage the Sensor itself Permanently (if strong enough, keep in mind, you have a crazy Bright Flash there, and the Lens will focus that onto a very small area. You basically built yourself a pulse laser. Depending on Energy or Pulse time there can be damage Caused to the Sensor). If it is so bright that it overexposes so badly, maybe try using an ND-Filter (Neutral-Density, like Sunglasses for your Lens. They come in different Densitys, the higher the number is, the darker it usualy makes your image), those filters will help make your image Darker, and maybe this allready solves the Problem? I think this could be worth a Try.