Ipv6 prefix delegation/slaac not working when going from 1.3-rolling-202007010117 to 1.3-rolling-202009170118

I’ve been very stable on 1.3-rolling-202007010117 with pppoe, ipv6 prefix delegation using the config noted in my post at Ipv6 prefix delegation.. how to assign ipv6 to lan clients when using DHCP-PD?

I just tried 1.3-rolling-202009170118 out of curiosity and none of my clients are getting ipv6 addresses. I notice my VyOS internal interfaces are getting assigned /56 ipv6 addresses instead of /64 like previously.

I’ve gone back to 1.3-rolling-202007010117 and it is all working great like before, I’m not sure if this is a bug or a change in behaviour in the rolling releases ipv6 that I need to adjust my config for.

Please share your configuration.

Just a follow up here, thanks to the assistance from @c-po pointing me in the right direction.
There was a change in the syntax as documented in https://phabricator.vyos.net/T2677
and now it is working for me with the recent 1.3-rolling-202009280118 release.

The auto config updater worked for me but I added “set interfaces pppoe pppoe1 dhcpv6-options pd 0 length 56” in my case as well.