Thousand-Mile Driveshaft Bearing

[JBX66]

So yesterday I was driving my truck home when I heard this awful scraping noise coming from underneath the truck I pulled over as fast as I could and when I looked under the truck, lo and behold the center bracket for the driveshaft had ripped itself off of the frame. I put this bracket on literally 1200 miles ago, replacing the old one which had appeared to rust away (the rubber was gone anyway, so I had figured a new one would be necessary). I had a machine shop press the new u- joints and bracket into place.

Does anyone have any idea why this could have happened?