There supposedly was an agreement that Amazon wouldn't start provisioning them for a certain amount of time, but whatever amount of time was specified, they either didn't honor it, or it wasn't enough time.
We were also moving assets over to AWS, and all of these things going on simultaneously caused what we called the three-pocalypse.
We would occasionally run across issues with external sites or newly provisioned lambdas who were on Amazon's new 3.0.0.0/8 block, but we couldn't reach them because internally that IP address didn't exist.
At the same time, they would open up a small block to allow access to those external sites, and then some internal service would no longer respond. Repeat ad nauseam. It was also compounded by the fact that there are countless teams in GE and not everyone would connect with who made what changes.