Run the same scraping job with identical proxy configuration against the same target. Morning: 98% success. Afternoon: 52% success. Nothing in your code changed.
We've watched this pattern across thousands of URLs and multiple providers. The variance has nothing to do with configuration quality. You can't tune your way out of it. The web operates as a contested, shifting environment where timing determines outcomes as much as technical setup.
That 50-percentage-point swing destroys planning. Completion time estimates become guesswork. Resource allocation becomes reactive. You're building systems where identical inputs produce radically different outputs based purely on when you press start.