So, long story short...had my coolant flushed at 37.5k mi per the maintenance manual. Since then, the coolant has been slowly going down. I mean very slowly. The alert came on to refill the coolant after a couple of thousand miles. We were told it was probably just air bubbles working their way out, and got a top off. A thousand miles later, it was down again to the middle between the max and min, but the Refill Coolant alert was coming on frequently. Went back and they checked for leaks, couldn't find any. They told us they had no loaners so we could wait until next week to drop it off. Next week, still no loaners, so we just dropped it. Trip #4! They had it for a week, contacted Kia and ran tests, and they tell us this is a "known issue". They say there's nothing leaking, it has been flushed again and they made sure there are no air bubbles, but that Kia engineers are working on a fix for this known issue. And that's it. No fix so far, we're just taking it home and hoping for the best. My next step is to contact Kia directly and ask what the plan is, ETA on the "fix". They say it's perfectly drivable, but I'll be checking frequently to make sure the coolant doesn't go all the way down below the min level marker. Posting this hoping it will be helpful to others. I haven't seen any mention of this "known issue" anywhere else. I might know more when I contact Kia.