I've had Sony systems that move their shutter timing off periodic peak flashes in light level. This was in a lab with strobes, and try as we might, the darn thing would move its timing off the synced 30 HZ flashes, which we wanted to film. Sony's explanation was a software feature to avoid patterns in the video image caused by flicker in fluorescent lights on power line peaks and valleys. I imagine you might have something like that going on, Try changing modes to something that likes flashes and rapid motion, like "Sports mode".
I agree, the laser pulse may be acting like a remote, too. Aluminum foil taped over the sensor might work, note black tape is not always black in the IR, often its "clear".
Steve
Qui habet Christos, habet Vitam!
I should have rented the space under my name for advertising.
When I still could have...