I met weird situation both in current gen and next gen.
Please check attached.
A1 -> B1 -> C1 -> D2 should be existed.
A2 -> B1 -> C1 -> D1 should be existed.
Original image http://i.imgur.com/V5ljLYr.png
Correction,
A1 -> B1 -> C1 -> D2 should not be existed.
A2 -> B1 -> C1 -> D1 should not be existed.