Hi Parker,
the "double entry" in the log is normal, and expected, and has been there for a POST for quite some time.
It exists because for each incoming post, 2 items are sent to the log, the "header" (which appears when the POST arrives) and the Header and Footer which appears once the whole "post" has been received. Posts can be very big, and so the double log helps identify where very large posts are coming from. I think the Multi-Host (if I recall correctly) has a tab to show "incoming Posts in progress" which helps to understand how the server is being accessed for big posts.
So the "odd results from the server" are not caused by a double-post (there's only one post) and it's not caused by two Posts appearing in the log. So I guess tell us more about what makes the results odd, and we can go from there.
cheers
Bruce