The all-grain recipes seem to have an error too.
I noticed, for Split Open and Melt, there are two different hop addition amounts depending on which page you view the recipe on.
On the actual Big Brew recipe sheet page, it shows a 0.5oz Chinook addition at 60 minutes. On the featured article page that's scrolling on the website main page, it shows this addition to be 1.5oz at 60 minutes. Both recipes sheets show IBUs as 86. In order to get ~86 IBUs, it would seem the 1.5oz addition would be correct.