Hey Dan,
Have a really good look at the tear marks on the cage, are any of them old, that is, can you see if some of the tear/crack was here some time ago before it let go this time?
I looked at that but the grain at the tear seem consistently colored. However there appeared to be a very small void or differential in the grain where it snapped. The contributing factor was IMO the lack of CV lube. The bigger question, since there wasn't prior evidence of it leaking, is where did it go? I used the Toyota kit with dual grease tubes...each tube fully emptied into the boot. As I mentioned I've been under the rig lately; namely with the 1" BL project and didn't see any seepage. And above and beyond that I'm usually all over inspecting the CV boots as they've been a general problem on and off forever. Bizarre!