I agree with the possible light stress/heat (what lights are u using? cmh?led?) cause the lower parts look very healty, but hey, i would first point at the genetic....
Just few toughts...
Size gets rarely affected in bad conditions (aside from the lack of direct light) when we use selected clones,
Quality, density, appearance, terpens, weight they sure get affected by environmenta problems...
Ive worked for 7 years in weed farms and ive seen lots of problems , but always worked with selected clones, never seeds....
That peanuts like buds are quite common between the new polyhybrids.....even doh the spanish amnesia has always been a producer...if you got em from seeds you could never been sure about it....
Ive seen some progenies of seeds sold as gelato or shrbert that flowered with a joint worth of bud!.....crazy flavors doh.
In first LED run i burned the hell out of my seed crop,waaaay to much light waaaaay to much close, ruined ! but i still found some keeper, huge cristal covered colas sorrounded by hay grade buds...
I also have the feeling that under LEDs the phenohunt is a little bit more tricky because some genetics that have been bred under hps for so many generations will freak out with this new light sources......