Its a worldwide issue with these filters .... I'd say the o-ring theory combined with the fact that the taps themselves are fairly cheaply made would be the culprit. Jeabo (the maker of these filters) is a big company and should figure it out but like many Chinese manufacturers they only get a clue when their orders drop off. We would not carry these filters due to the issue despite the easy fix. We simply can't carry a product that requires immediate modification/replacement parts to be installed before reliable operation can be enjoyed. We need products that work "out of the box" and the CFS500 doesn't do that. People who already own these filters are lucky that Gunner has done the homework and figured out the solution IMHO.