Have you personally had this issue? I personally have had multiple customers at the parts store come in with Ioniq 5s asking for the 12V battery to be tested. So far they've always tested good. When the battery tests good, I ask people what led them to come in and/or what the problem they are having with the vehicle is. Usually they tell me the car has a 12V battery error on the display or it's just acting weird.
I don't start going on about how these ICCUs are an issue, I just tell them kindly that they should take it to the dealership because I've heard there may be software updates available. Ultimately my hope is that they can have the issue addressed before the car leaves them stranded. But I don't want to scare them or make them think they have a bad car.