If an admin manually terminates an instance, i.e. not by decrementing the autoscaling group "desired" field, then when the ASG notices the machine is no longer available and start performing the "terminating" life cycle action, the instance no longer has an IP.
As a result, the lambda-route53-updates can't figure out which IP to remove from the RR set and the old IP stays in Route53.
If an admin manually terminates an instance, i.e. not by decrementing the autoscaling group "desired" field, then when the ASG notices the machine is no longer available and start performing the "terminating" life cycle action, the instance no longer has an IP.
As a result, the lambda-route53-updates can't figure out which IP to remove from the RR set and the old IP stays in Route53.