[Tristan Lall]

It's illegal for another reason. See figure 4-5, top left and figure 4-3, top left. You've drawn one of those two scenarios (but I can't tell which, because there's no top view), both of which are illegal—the former because the corner is unprotected, and the latter because there is hard material extending too far beyond the corner. (You can tell it's one of those, because the end face is uninterrupted. If it were one of the legal configurations, the bumper backing would be stepped back and only the cushion would be in the corner.)

Correct it by using any of the other ("OK") examples in fig. 4-5.

(Note that the fig. 4-5, top left case has been variously legal and illegal in past years. The fig. 4-3, top left case has always been illegal.)