Today, Amazon VPC added a new feature to its DHCP option set called IPv6 preferred lease time setting, which allows customers to adjust the frequency of IPv6 lease renewals. This feature gives customers the option to increase the preferred lease time of IPv6 address assignments on Amazon EC2 Nitro instances to minimize the number of IPv6 lease renewals and prevent possible renewal failures. This setting applies to both dualstack and IPv6-only Amazon EC2 Nitro instances in the VPC.
Source:: Amazon AWS