Yup, sounds like testing is needed to make sure, and i think the LFS owner would honestly want to do that, and not deny anything is wrong right off the bat.
Either the carbon is exhausted , or maybe even something like a sytem line is routed the wrong way, possibly bypassing the carbon, who knows

.
It affects you and whoever else is using that RO water, so i would think the owner would be concerned since i would not want to be the one responsible is something was "off" in making the RO to sell.
Keep us posted on what ends up w/ this,,