Some builder do not use quality help. I have seen some, see earlier post, that have 10 guys doing one engine and non of them seem to know what the other has done. I have seen two different size heads, one type of piston on one side and another on another, rods installed the wrong way on the pistons, two different size bearings in the same engine and on and on.
Can you tell what size the bearing that failed was? Shoud be stamped on the back of the bearing. Pull the next main cap and compair the size. Also look to see how the bearing is wearing. I have all so seen some cranks turned out of round that is to say they got tapered during poishing.
Were the bolts tight? A bearing can fail if it is to tight or if the
oil flow is not up to were it should be. It can also fail if it is not installed correctly. I do not see how it could be the bearing at fault. We use Clevitte in a lot of our engines and have never had a failure.
I am really sorry to hear about all the bad luck you are having. Makes me mad and sick at the same time.
It is late on my end so I will check back with you in the morning to see what other fun things you have found.