Don't want to sound like a worry-wart but I would still be a little concerned about the coil-bind issue. If they were binding that bad, it would be pretty hard on the cam, especially a new one that had not been broken in. I would go ahead and change the oil again, and check the filter for metal. I am saying this so that you can cover your a$$ if the cam goes away after a few hours. I would be asking the builder if he will cover you for a new cam if this happens in the near future. Something like coil bind should have been picked up by a good engine builder, and if the cam wipes out because of this, it is TOTALLY HIS FAULT and not yours! Make sure that he is aware that you know this. Also, did he explain why this happened in one engine but not the other?
Wishing you many hours of enjoyment with your new motors!!