High number of engine failures for 2015 kia optima not in reliability rating?

What is your question?

The third generation kia optima, 2011 through 2015, is plagued with engine failure. Why are all those engine failures not reflected in the repairpal reliability ratings for those vehicles. The common problems listed do not include engine failure, even though that's the most common problem for 2011 through 2015 kia optimas. Why is engine failure not listed?