There have been a few occurrences of the oil filter adapter coming loose from the engine block. What you describe sounds to be more than a valve gasket leak and too sudden ....
I changed my valve gasket last summer....rather straight forward..piece of cake
www.avigex.ca/kia/gasket1.JPG
www.avigex.ca/kia/gasket2.JPG
www.avigex.ca/kia/gasket3.JPG