The only issue I can find is the fact that, obviously, for some reason the figures/shadows aren't registering with the camera(s), but they are appearing without recorded acknowledgment.
From what I have experienced (and I know, a lot of others here, too), spirits and the sort *can* mess with a camera's capabilties. However, what stumps me a bit is the fact that when played back, the recording is untouched, besides the fact that the shapes aren't captured.
How are you seeing the shapes? Is it across the viewfinder, an attached digiscreen, etc.?
What may be occurring is the spirit is not passing across the actual view of the lense... but through the medium itself. Due to its high energy field, it is makng an imprint, if you will, in the immediate field of vision, therefore distorting what you see on camera, without actually "being on camera."
Does this make sense?
So in this case, I wouldn't necessarily alarm yourself to the "black shadow" connotations... it could simply (if you CAN view this simply!) be the energy distortion you are seeing.
EX: Think of it as a magnet... and what happens when brought too close to a television, etc... what you are seeing is a manipulation of the otherwise *perfectly* broadcast image.