Are you talking about sinking your motor mounts into our frame? If so, it is common for early model current gen tacos, happens on some FJ's and has only happened on 3 4th gen 4Runners that I know of (mine being one of them).
This is only happening to people who wheel their trucks hard in fast runs. All the cases I have seen were guys who wheel hard in the desert. There will not be a TSB for something like this. There is nothing defective about the trucks, it is just a weak point- which is totally different.