Wet straight through a Sandys and wool cover

[HappiMom]

I'm talking a puddle on the floor. Both the cover and diaper are new and this was a first time use.

The wool cover (ecoposh) wasn't wet on the outside, so I don't think it was the problem. I think I lanolized it pretty well, even though it was my first time. The pee ran down her leg and I am wondering if the Sandy's is too big? My DD is 23.5 lbs, so I bought a large bamboo terry and it closes on the tightest setting, but still feels kinda loose. Do you ladies find this diaper runs big? Maybe I should have got a size S??Most mom's here do not complain about this diaper leaking.

I am wondering if I need to wash it a couple more times to boost absorbency? I only washed it twice.