PD broken in v4.3.2? prefix6 start prefix is outside the subnet

[Chris Buechler]

DHCPv6 PD configurations that worked in 4.3.1, 4.2.x, and earlier
versions have stopped working in 4.3.2. For instance, this
configuration will no longer work.
https://kb.isc.org/article/AA-01093/0/Adding-class-support-for-DHCPv6-in-ISC-DHCP-4.3.html

every instance of 'prefix6' I found in this list's archives will no
longer work, examples all over the Internet like this no longer work.
http://www.tldp.org/HOWTO/Linux+IPv6-HOWTO/hints-daemons-isc-dhcp.html

You end up getting "prefix6 start prefix is outside the subnet".

That's a result of this change noted in the release notes:

- Added checks in range6 and prefix6 statement parsing to ensure addresses
  are within the declared subnet. Thanks to Jiri Popelka at Red Hat for the
  bug report and patch.
  [ISC-Bugs #32453]
  [ISC-Bugs #17766]
  [ISC-Bugs #18510]
  [ISC-Bugs #23698]
  [ISC-Bugs #28883]


range6 I can understand. prefix6 seems to be a mistake though. Of
course it's outside the subnet, that's the nature of PD. There has
never been a requirement previously for prefix6 to be within the
declared subnet, and it worked fine. Now I can't find a conf file
anywhere that actually works with PD, across a variety of
circumstances that worked on 4.3.1 and earlier.

Is there something I'm missing here, or is PD actually broken?

Thanks!
Chris