Professionals in the field of search and rescue, coroners and police detectives, who are also deputy coroners, don’t operate by guessing at the cause of death. I do not believe you would find that “guessing” is an option in any of their training when it comes to assigning cause of death. So, once you give them, or their professions some credibility, the disparate three causes of death make absolutely no sense. It clearly is a case that calls for investigation which the law demands so why not just do it?
If a soldier dives on a grenade to save his squad, or if a car crash victim has a piece of the vehicle impaled through his stomach, then it does not require an autopsy to ascribe "internal injuries" as the cause of death. However, in Fuddy's case, there was no such obvious external sign correlating to internal trauma. A conclusion of internal injuries would require examination of the internal organs, which the Coast Guard did not do.
So, yeah, either someone was guessing or some error in transmission of the message occurred.
It clearly is a case that calls for investigation which the law demands so why not just do it?
And Maui did that -- they conducted an autopsy (a medical investigation into the cause of death) on Ms. Fuddy. But the law does not demand Maui employees go and find out why some Coast Guard person ascribed a different cause of death.