Understanding what's going on with our cameras. motion sensed but just a light show

Hi we are trying to understand what is going on on the cameras. this was recorded last night at 1.12 and there is another one at 135am. but i can only link one of the cameras footage. as i am not allowed to post more.
The cameras say person detected. any idea what causes this type of footage.
2 cameras that are out side Did not pick up anyone or anything.

Thanks Julian