Here's the way it was explained to me by an engineer at an appliance
mfgr: Because everything has been taken out of the RO water, it acts
like a solvent and dissolves minerals in the metal of the holding
tank. He said that after several years of running RO water through
those tanks and water lines they develop pinhole leaks.

It's the same reason you're not supposed to use RO water in a steam
iron. I have a Rowenta iron and it specifically states not to use RO
water, only distilled.

Hey, I don't make the news. I just report it.