It may well be the education. I leave my family members in my capital with a fully upgraded academy from age 16 to at least 24 unless they show very early promise and are made generals of one of my armies. It is these poindexters that I tend to send out to govern the frontiers since they build up nice management and generally at least grab some nice influence ancillaries. Maybe I should try retiring one of my great yet uneducated generals in a frontier city and see if he becomes a defiler of the gods.