From the OP:

> a policy change was inserted into the regional Spanner tables that Service Control uses for policies. Given the global nature of quota management, this metadata was replicated globally within seconds

If there’s a root cause here, it’s that “given the global nature of quota management” wasn’t seen as a red flag that “quota policy changes must use the standard gradual rollout tooling.”

The baseline can’t be “the trend isn’t worsening;” the baseline should be that if global config rollouts are commonly the cause of problems, there should be increasingly elevated standards for when config systems can bypass best practices. Clearly that didn’t happen here.