The only problem I have seen is that your odhcp6c was not running, not sure why.
Other than that the ipv6 over dhcpv6 works by default.
Keeping configuration over major releases is not advised, as there can be differences in the options. Same applies for migrating configuration over different devices.
The only thing I believe that fixed the problem was the reset you did after flashing 17.01.7
Since the problem is solved, feel free to mark the topic accordingly.