Re: The processes failed before the strut did
Reading about the Apollo 13 mission, process failure happened then as well. By all accounts, the O2 tank failure was due to a combination of the tank being dropped slightly during a test five years before the mission flew, plus the tank thermostat manufacturer not getting the memo about the shift from using 28 volts to 65 volts as part of the response to the Apollo 1 fire.
Space.com has a writeup about the incident.
Universe Today has an excellent series of articles about the incident. By curious twist of fate, the damaged vent pipe probably saved the crew from death as the tank stirring procedures had been accelerated to try to deal with the issue - it failed on the fifth stir, but whilst still in space with the lunar module docked, instead of on day 5 as scheduled, with the mission already on the lunar surface.
It seems the tank passed all tests as an item, but the combination of parts made a small bomb. The workarounds were accepted instead of triggering a concern, but then the timescale and complexity of the endeavour pushed the issue down the scale.
SpaceX is a lot smaller and responsive than the Apollo programme, and is data-rich. Some suggest bringing it all in house is a way forward, but they haven't the capacity for this. Keeping everyone communicating is more important - this rocket science thing is no place for folk to hide substandard work, for example. That they can pin down the cause is testament to SpaceX setting up systems to let them learn from every launch, not just the failures.