Colibri49
While what you say might be true, the complexity of these machines, and the stresses involved can create unexpected outcomes.
Perhaps the making of metal in the REDL case was unrelated to the subsequent catastrophic failure. (A "red herring")
This scenario would make the mitigation applied (to detect metal particles earlier) ineffectual.
Obviously I have no more idea about the cause of this latest tragedy than any other EC225 pilot.
Like everyone involved I hope the actual cause is positively identified. Unfortunately this outcome is far from assured.
There are many potential sources of metal fragments in a transmission. Some more benign than others.