No, within the last month.

One thing is that I don't see anything about auditing for Keyoxide, but Keys is up-front with a warning.

Keyoxide doesn't use any cryptography, everything is handled by identities in PGP. I doubt it needs any auditing.

The only reasonable attack vector I can see is hijacking the website (or proxy server) to return different keys or show something is verified when it's actually not.

I haven't checked quite what Keyoxide is doing, but I'm not sure cryptography is the only thing worth auditing for security.