Without knowing what went wrong and where, we could speculate about this all year long. It could have been spec'd correctly and an uncaught error made down the process but we'll never know unless Lionel says what happened.
I remember back in the "Mike Regan era", Lionel had a "Quality Control Inspector" over there in China. So,,,,what happened to him, and why wasn't this reported "sound mistake" found by that "Inspector", over in China prior to any models even being packed?
Yes it stinks to have to return it but it does seem like Lionel is stepping up. I'm not sure if Dean's hair could get any grayer. LOL! I'm sure he's doing his best.