I've never heard of this before either, and we have used WNNN for over a year. I have never had them done up on anything other than the 2nd loosest setting on the waist, and loosest setting on the legs though. Maybe the fleece soaker was too tight? Fleece doesn't really stretch much. Hope you work it out so you both get a good nights sleep tonight x
I agree, gape is fine on the legs. Our night nappies are quiet loose on legs and waist, we use a tots bots fleece wrap which isn't at all tight on legs or waist , and usually is gaping so you can see the nappy sometimes, and don't have leaks as long as the nappy itself isn't peeking out.