Exactly. "Complex systems almost always fail in complex ways." If a system is complex and yet stable enough that it's running in production, it's frequently running in a partially degraded state and at least partially resistant to single component failures. Noticeable failures reaching the level of root-cause analysis almost certainly involve multiple component failures, each with proximate and root causes. Recursively decompose those component failures if the components themselves are complex, and you're left with many "root" causes.