CDN speeds not consistent and failing sometimes

Hello there, I’ve a bunny CDN bucket for my static assets and a worker to sort where the request should go, lb or bunny bucket. If the request has /assets/ goes to the bucket, otherwise, goes to the origin. The problem started when I tested the site speed with WebPageTest to see the improvements vs my old deploying strategy. I see that the timings change a lot from 50% faster to 200% slower, I tested serving the assets directly from the bunny bucket, and It improved the 50% consistently. Am I doing something wrong? OBS: I tested around 50 times (3 runs per time) to see if it was a momentary thing, I used other services for testing (i.e. Page Insights and GT Metrics)