I received my replacement ESC's from Castle. They sent me two brand new units with "new stock" labels. That's great, and I'm happy their warranty service came through. However, they had no reply or explanation as to what happened or what exactly failed. I guess they probably just pitched the failed ones out and sent me new ones. It's pretty normal these days to do that with electronics.

I'm not sure what to do with these. I will probably put one in after the season is over and see how it goes. I will check and see what firmware version they loaded into them and I won't update them. It seems that all my issues started after I updated firmware on the three that failed.