Smelly inserts...Help!

We've been CD'ing exclusively for 3 months now, I've noticed in the past few weeks that the inserts for our Fuzzibunz seem to be smelling a little off (kind of funky) when we've just finished washing them and that 'off' smell gets worse when she pees. I've made sure we aren't using too much laundry soap (Tide free), we only use the half an ounce suggested on the back of the fuzzibunz packaging. I've washed just the inserts with bleach. I've set them out in the sun. I'm not sure what else to do. We don't use diaper creams or anything that could cause this smell. Have any of you run into this problem before?