Engine Warranty Help?!

Hey Reddit! I have a 2015 Kia Optima SX with the 2.4L. The car has 201,800 miles but the engine was replaced already at 120,000ish.

The new motor went out. I read the code and it’s throwing P1326. The engine has a knock, and the enging light is flashing. Here is where my clarifying questions begin.

• I have read that the engine warranty is a lifetime warranty, regardless of being outside of the normal manufacturers warranty. Is this accurate?

• Because the car is outside of the manufacturers warranty I have been replacing some of the parts myself. One of them in a non-OEM Catalytic Converter. Will Kia not honor the lifetime warranty if that Cat has been replaced with an aftermarket Cat?