did anyone get a linea nigra for one pregnancy but not another?

for LO#1 i got a real dark one (i'm asian and have a tanned skin-tone) and it faded really slowly. By about 7 months post partum it was still visible but much fainter than during pregnancy. I got pregnant again with #2 (also a boy) at 7 months pp and I've been waiting for the line to get darker again -- I'm 32 weeks now and it's still the same faint line! Interesting..... not complaining though, I prefer not getting it at all