Lots of people speculating that Toyota must have known about these issues when testing the engines. I'm giving them the benefit of the doubt. I bet they were built without machining debris and the bearings held up. The change to the bearing is a response to the fact that they are not sure...
I wouldn't think any 22 is safe. it seems intuitive that there is a likelihood of machining debris in the engine. And... without the improved main bearing.... a likelihood that debris will cause the bearing to fail. My hope is they get it resolved and give everyone affected a new engine...