The best way I can describe the noise is some sort of pressure release. Air, hydraulic, something else, I'm not sure. There is no fluid of any kind on the garage floor. It only last for less than a second. This issue has been present for over a year and I only notice it if I happen to be in the garage at the right time. Then it could be weeks or months before I hear it again. It seems to happen after the vehicle has been parked for an extended period of time. All regular maintenance has been performed, by myself or a Kia dealership. I haven't experienced any other issues or problems since I purchased the vehicle new.
My car has 27800 miles.
My car has an automatic transmission.
The vehicle after shutdown can go into some tests for the fuel tank vent control to test the fuel vapor systems. This is a normal condition and should not be a problem. If this ends up becoming more persistent, and seems to cause a problem, you can have the noise diagnosed by a qualified technician from YourMechanic.