I would hold back the bright spider for sure.
Either could be the reason for the brighter babies.
I think I remember seeing a post somewhere on a Het Hypo to normal that produced several brighter offspring.
If I remember right they all proved out to be het.
More photos of her might help out.
I wouldnt call anything that vague genetic, especially on only one clutch. It is sad that many people will though. Just have a look at WOBP