Had 4 flights today. 2 in the am, then took a break charged batteries and then 2 more in the pm. When reviewing video and photos from am flights, realized nothing from first battery was saved. Figured it was operator error, but copied everything off the card and then reformatted it. After evening flights found exact same thing. Reviewed video from controller and found it was not operator error. Anyone ever heard of that before? In summary, nothing saved from first of two batteries.