Yes, there are a number of oddities with that region.
They finally removed the weird "S3 buckets are global, but really they're just in us-east-1" problem, but there are still a number of global API endpoints that are hosted there. This can make locking down regions that can create new resources difficult if one of those regions isn't us-east-1.
Regards,
-scott
Welcome to Rivendell, Mr. Anderson.