Arno, Thank you so much for your prompt response. Very interesting that it's working as expected for you.
At least I can isolate the problem to being local for my network. I asked about this in #debian on irc, and it was suggested that I check if I use dhcpv6 or dhcpv6-pd. I'm not 100% into ipv6 terminology, but I think my ISP uses dhcp-pd to give me a prefix. Other than that I don't think dhcpv6 is in use. I use SLAAC with and without privacy extensions (basically, a complete default setup). In any case, I do not believe that my ISP changed anything in those 30 minutes it took me to install bookworm, so I can't understand why it behaves differently. I'll have to dig deeper. Thank you for input and comments! Best, Andreas
