I respectfully disagree. I'm all for root cause analysis and taking the time to fix things upstream, but I also think that it's easy to say that and hard to actually do it.

Yelp doesn't make more money and our infra isn't particularly more maintainable when I invest a few weeks debugging Ruby interpreter/library bugs, especially not when there are thousands of other higher priority bugs I could be determining the root cause of and fixing.

For context, we spent a few days trying to get a reproducible test case for a proper report upstream, but the issue was so infrequent and hard to reproduce that we made the call not to pursue it further and just mitigate it. I do believe that mitigate rather than root cause is sometimes the right engineering tradeoff.