Amazon S3, you're out of order
m.signalvnoise.com
m.signalvnoise.com
I'm guessing this is Direct Connect out of the Equinix/Ashburn location, so they are probably working with a partner. There are probably a few black boxes in between their servers and AWS S3 edges. If this is affecting them I would expect to see a lot of people seeing the same thing.
I'm not really surprised an AWS support team shrugged it off but it seems like there are some more pieces to this.