Here it is:
And without it the flange-web transition interferes with the bend you need to make.
Well, the drawing does show a notch if one looks closely. But in looking at the completed structure, I see no need for it, the bend is so gentle and it is all riveted together forming one solid piece. There won't be any bending or flexing in the that area and the bend itself places no stress on the piece. It is actually slightly outside the flange joint.
Perhaps Vans needs to clarify the matter. There have been plenty of 8's built and it is interesting there is no mention of a notch in section six.
I can't believe one as to review a drawing in such detail (a magnifying glass would help) with no written reference to it. If the drawing had a note "this notch is important, do not omit it" I would appreciate its importance. But there is no such note. The drawing also appears to show 810 and 814 notched, I don't like that as it would weaken those parts.