I’m not real familiar with the Kias but most vehicles like this use mechanical valve lifters. This means that valve lash should be inspected and adjusted regularly.
If not, it’s possible for a valve, or valves, to tighten up and prevent their closing. This in turn will burn the valve face and valve seat. This is most common with the exhaust valves.
Look in the owners manual, under the hood, or on the upper radiator support for the specifications sticker and see if there is a reference to valve lash. If there is, run a compression test. If cylinder 3 is down start expecting the worst; as in time for a complete valve job.