Good news, my boss talked to me before I went home today
. I feel like I'm dealing with my wife having a little silent treatment tantrum.
Anyway, when you receive the bearings are they completely demolished? If not, I would think you could rule out contamination or overload pretty quick. Don't they have different damage signatures?
Since 1 & 6 take more load then 2-5, overloading seems a good choice, but I think a closer look at the bearing surface and subsurface would tell more.