wow I didn't know your numbers were so extensive, so if im reading it correctly, every single one of the 153 spider offspring from the spider x spider pairing was bred to see if they were homozygous? Also I saw a thread that claimed to produce an all white snake that died after hatching from a spider x spider pairing, you never saw anything like this?
the "normal" making spiders is quite interesting also, few explanations that come to mind right away. (can we get a picture of her for the heck of it?)
simple one would be she is a spider that pattern resembles normalish quailties (im sure you thought of it already),
she could be a paradox, having spider reproductive organs,
she is a spider, but also has a recessive trait that dominants over it, making her look normal
epigenetics is at play and the expression on the spider gene is turned down, or even off.