The relevant part is that distilled water + osmosis makes cells burst. So, we're talking about tiny injuries, not just some mineral inbalance.
As far as I understand, once it's in your stomach, it'll get dilluted and then it really is just water with too few minerals. But on the way into your stomach, it can cause damage.
We likely don't have scientific data on how much/frequently you'd have to drink it for the body to not counter-heal enough. But yeah, just don't drink distilled water.