Every time I logout, I get logged in to HN as someone else

I came home from work a few minutes ago, hopped on HN, and I was logged in as some other random user. I have no idea how, I've never logged in to HN on any computer as anyone other than this account.

Even stranger, when I logged out, it automatically switched to another user! Clicking it a third time, and I was logged in as a third random user. Finally, after 3 attempts to logout, it finally allowed me to login as me.

Anyways, I'm sure someone probably wants to know about this.

It was a cache directive gone wrong. Shouldn't still be happening.