I like this one too:

After removing various bottlenecks in our system, SimpleServer scaled to 20 cores and serves nearly 700,000 requests per second. This workload places an unusual burden on the Linux kernel and triggers a bug in Linux; Under such a heavy load, the epoll subsystem occasionally does not return read events for a socket, even though the socket has data ready, causing worker threads in SimpleServer to wait for data indefinitely.

[...]

This long-standing bug affects all Linux kernels since 2.4 and a patch fixing the issue has been accepted into the Linux kernel

In short their "simple server" with the Mio manager was so fast that it broke epoll :)