I see this as a major feature gap that can cause a lot of frustrations. There is no “ipv6hint”, “IPv6 Prefix ID” or similar named function to “pin” a prefix from the PD pool to a specified interface. It is essentially random. Add/delete/change an interface and the IPv6 address can change on all interfaces without warning.
This is high on my wish list. I’ve personally never worked on a routing platform that doesn’t have this type of capability.