@Lari_Luoma and @_Val_ and the community,
After enabling IPv6, reboot one security group member followed by a crash of the whole Maestro environment and a following discussion with TAC...
Following Gaia R81.10 Administration Guide (System Configuration) (After you enable or disable IPv6 on a Security Group in a Scalable Platform, you must reboot all the Security Group Members at the same time) we had to reboot the whole SecurityGroup to enable IPv6.
This indicates a complete downtime for the Maestro environment, meaning approximately 30min with no traffic flow. Very bad behaviour for a highly available scalable environment. We and our customer are not happy with that solution.
Yes, we could enable IPv6 before deployment, but we don't want to enable features from the beginning we don't need.