Don't worry about any response from Ward on their point that elements buildup in filters. Unfortunately if they made that statement, the folks at Ward's know little about water treatment. An activated carbon filter does not remove the ions that affect brewing water chemistry. It primarily removes organic compounds and some heavy metals. It also catalyzes the destruction of chlorine and chloramine. Ca, Mg, Na, SO4, CL, and HCO3 are uncaptured in either activated carbon or particulate filters.
You don't need to worry that the filter will 'unload' its captured materials into the filtered water. The same thing applies to particulate filters. As long as you aren't shaking or otherwise disturbing the filters, they won't unload either.