"Engines prone to failing the test are mostly in hot climates and use synthetic oils."
People cant use synthetic oil in their Rotary engine... it does not burn properly compared to "dino" oil, and leaves gunk which in turn ruins everything else. (Burning oil is an integral part of the lubrication and cooling of the Rotary). The owners manual doesnt say to use it and if you talk to Mazda North America they'll say they dont reccomend it. Expansion in hot running Rotary engines also lessens the compression ratio - especially in hot climates.