ipv6 dhcp status change (na-valid / na-address)

Hi, I have LTE interface with IP ipv6 address (request type = address). I would like to update the bind to dns name, when new ip address assigned.

How does na-valid and na-address are supposed to be used in dhcpv6 client script?
This does nothing:

#:if ($na-valid=1) do={
/tool fetch mode=https keep-result=no url="https://www.duckdns.org/update?domains=aaaa&token=bbbb&ipv6=$na-address";
:log info ("ip address changed to $na-address");
#};

The output to the log is “ip address changed to -address”

What am I doing wrong?
@Janisk

Any help, please?

Try construct the url upfront using $“na-address” & $“na-valid” instead.