Also known as Fundamental Failure Mode. From Systemantics:

System failure

The Fundamental Failure-Mode Theorem (F.F.T.): Complex systems usually operate in failure mode.

A complex system can fail in an infinite number of ways. (If anything can go wrong, it will.) (See Murphy's law.)

The mode of failure of a complex system cannot ordinarily be predicted from its structure.

The crucial variables are discovered by accident.

The larger the system, the greater the probability of unexpected failure.

"Success" or "Function" in any system may be failure in the larger or smaller systems to which the system is connected.

The Fail-Safe Theorem: When a Fail-Safe system fails, it fails by failing to fail safe.