I think its the Dub in the genetics, which has shown to be sensitive to duds already. But what im referring to are predatory root/stem nematodes which are detrimental. Beneficial nematodes don't cause duds or problems. Predatory ones get into the plant and can pretty much stay forever, then if you provide optimal environments ie too wet of medium, they thrive and produce duds. With GG4 you def need a dryer cycle.
As for cut difference- I don't think its necessarily different cuts. Mine looked like yours last round but under
gavita light is stacking way better. And though I don't think there are different gg4 cuts, i think the different sources make a difference. I mean mine went through several gardens before it got to me, and has shown occasional duds since (and no its not from LA or a dudded clone). Homies closer to the source seem to not have the issue and some show more vertical growth vs horizontal branching.