One example might be rate limiting. Count requests over elapsed time. If elapsed time is a negative number, the math might trigger a bug that causes CF to block requests...too many requests over time period X.
Cloudflare posted a post-mortem [1]. They were measuring round trip time, and supplying the result of that into the golang rand.Int63n() function, which panics the process when given a negative number.
[1] https://blog.cloudflare.com/how-and-why-the-leap-second-affe...