Inadyn "updating" my unchanged native IPv6 every time it fires

[jetkins]

I'm running 3004.388.8_2-gnuton1 on my ZenWiFi AX router. My host, Google Fiber, supports native IPv6, so I have that enabled and it all works fine. However, looking at the log for the first time in a while, It seems that when the DDNS fires every 30 seconds to check if my address has changed, it gets confused by the link-local address on my WAN connection, and forces an update of my IPV6 address with my DDNS provider:

Oct 29 01:21:36 watchdog: start ddns.
Oct 29 01:21:36 ddns: update WWW.DYNDNS.ORG default@dyndns.org, wan_unit 0
Oct 29 01:21:36 ddns: Clear ddns cache.
Oct 29 01:21:36 ddns: Start Inadyn(9).
Oct 29 01:21:36 inadyn[6350]: In-a-dyn version 2.10.0 -- Dynamic DNS update client.
Oct 29 01:21:36 inadyn[6350]: IPv6 address fe80::7e10:c9ff:fe7a:89a0 is not a valid Internet address.
Oct 29 01:21:36 inadyn[6350]: Update forced for alias redacted.homeip.net, new IP# 2605:a600:redacted:1
Oct 29 01:21:37 inadyn[6350]: Updating cache for redacted.homeip.net

This seems to be bordering on abusive, and I'm surprised my DDNS provider hasn't complained, but I'm unsure whether it's a problem with the inadyn updater or with the way it's being invoked. Any insight is appreciated. Thanks!