tl;dr - Turns out Amazon SES has an IP that is currently blocked by Spamhaus

Imagine my susprise while investigating some email delivery issues lately when I discovered that Amazon SES was using an IP that is currently blacklisted by Spamhaus!

The IP in question is 54.240.27.189 and of course I took images to prove it happened:

And there ya have it – I don’t know what automated system is going to ping someone (or another robot? is it robots all the way down?) to go fix this, but they’d better get to it.