It looks like the one in your yard is actually a digital relic in your camera from the main strike as they have the same shape. I assume the main strike behind the tree was the main strike and the first picture in the sequence. I know how it could happen on a film camera but not sure how that would happen on a digital camera unless it was an imprint from the lightening flash temporarily on the lens.
Thanks. And it must be an artifact. I can see now how it matches the bottom of the main bolt. But it is the first frame.