I think I may have found an error in one of the variations for this pattern (328765 - sorry the site won't let me post the link in my comment). The colours A & F and B & E seem to be reversed when you compare the last row of the pattern to the first row. I was able to work around this by doing a forward-backward knot for the third and fourth knots of the first row, and a backward-forward knot for the sixth and seventh knots.