Could this be related? Today we got an email from Amazon that our EC2 instance server has degraded hardware. We have until June 16 to spin up a new server before they kill this one.
... only I had already spun up a new server. Because the existing instance wasn't working. Getting their system to terminate the old instance required several attempts and force termination before it succeeded.
Considering their scale, I would expect better handling of the edge cases.