Purchased ours in late October, failed by mid November. Dealer initially said it may have been hit by another car. What a dumb thing to say with no obvious signs of damage! The scary part is that this dealer didn't seem to know how to address it so they did a simple reset to clear the error on the first visit. It failed again during the 10 mile drive home. Had to make another service appointment and took it back two weeks later. On the second visit they talked about having to drop the rear bumper to replace sensors. Fortunately it didn't come to that and they ended up doing a complete "software update" to clear the error. One thousand miles later and the error came back for the third time. I'm scheduled to drop it off tomorrow, 12/26.
It's really frustrating having to keep going back for this issue, but more importantly when ours fails it seem to affect other safety functions.
Hyundai better get their act together and find a fix. We love our Palisade Limited and hope it doesn't come to us having to research California Lemon Laws!

Keep us posted on what your dealer is saying regarding these failures, and when we can expect the new software updates.