This happened to a friend of mine and she established it was her daughters wee,. We swapped one BBH each and marked them, the one of mine she took started disintergrating where as the one i had got no worse. Hemp lasted longer but all her bamboo disintergrated, after replacing a batch and the brand new ones doing the same in about 2months she gave up on cloth. :-( she had already full time clothed her elder DD so she was not one to give up easily.