This seems to indicate (at least as a possibility) the root cause of this event was a fan blade broken.
After this, whether the blade itself remained "contained" but something else was triggered (some other piece went off as a result) which in turn caused cabin damage etc, in my opinion is immaterial.
I stand to be corrected!
Lawyer speak
"had it not been for..."
But in aviation we work in balancing risks so the regulatory aspects recognize that nothing is perfect among all the systems including their human maintenance and operation.
Thus the operating words are
"in spite of"
precautions need be taken to etc. etc.