When the radiator was replaced, the Honda technician and his “expert” consultant (Honda trained as well) injected some sort of dye and tracked its flow. It was then flushed thoroughly, given a one-hour test drive and let idle for an hour(? - long time as I recall). They were convinced the problem was solved at that time, but the same mix of antifreeze and oil? is what is presenting again. It is an emulsion that settles into three bands: green antifreeze on the bottom, brown (less viscous than oil) liquid in the middle, and then the frothy brown on top. I kept a bottle of it to show any other shops we check out. Good to hear that the cracked block is a rare occurrance.