You don't have to decipher the author's intent. All you have to do is find either a version of the sentence that expresses a meaning that makes sense or the version of the sentence that expresses the meaning that makes the most sense.
The idea that you have to decipher the author's intent is basically a myth.
For example:
Sitting in its nest grooming itself with its beak, John saw a bird.
John saw a bird sitting in its nest grooming itself with its beak.
The first of the above examples conveys a nonsensical meaning. We don't have to worry about the "author's intent." All we have to notice is that the meaning conveyed is nonsensical.
Then, we go to the second and, without wondering what the author's intent is, we see that it makes sense. So, the second would be the correct version.