I try to use a Mikrotik CCR as a IPv6 Gateway for a bigger network. Client CPE gets its prefix via DHCP6 PD. The CCR has a DHCP6 Relay configured but does not install the prefix it hands out to the Customer CPE into the local routing table. When I configure the DHCP Server locally on the CCR the route gets added to the table.
I ended up enabling DHCP logging and writing a script to read the log and add the prefix that way. I have the script on a scheduler and running every minute. Quite a pain, but it was the only real automated way I could think of to do it.