As many might have noticed, there is a variety of cars available the offer RHD animations and layouts. However, when I try to load up my game with two RHD cars installed, the game crashes during load. I've noticed that the all share a common layout in the dlc.rpf\data\ai section with a vehiclelayouts.meta file. Could it be a data conflict within the layout settings in vehicles.meta and vehiclelayouts.meta? For example, I tried loading the YCA ER34 and another RHD car at the same time but it made all addons invalid or crashed on load. But each car works perfectly individually.
TL;DR - Having two RHD layout addon cars in-game causes problems. But both addons work fine individually.