> Set IPv6 Connection to SLAAC (this is critical - SLAAC must be used, not DHCPv6) [...] Set 'Prefix Delegation Size' to 56

Is this also A UniFi bug, is Starlink doing IPv6 address assignment in a weird way, or is this a normal/RFC-compliant way of assigning a /56 subnet to a router?

I always assumed routeable prefixes on v6 require DHCPv6 (except for hacks like RFC 7278 and /64 subnets)?