Not sure if it is in the A-20 as well, but with the Boston it looks that way due to how the wings break. They don't snap cleanly in half, they leave a small sliver of wing up front and just take a chunk out of the back part of the wing.
Basically it turns from this:
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| | [Plane here]
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To:
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| | [Plane here]
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Depending on viewing angle the sliver left can't be seen. Again, not sure if A-20 does it, but it is how some planes wings break. Try using F3+F8 and moving the view around to see if that is the case of not.
