September 2024 I ended Dynamic DNS service from dyndns (seemingly no longer working) and set up my G34 DDNS settings correctly with https://freedns.afraid.org/ 

To confirm it was working, I manually set an incorrect address at freedns.

Then I disconnected the G34 coax (simulating a network outage) and reconnected. After some time freedns showed the correct address so the DDNS update that ran after the cable network was restored must have worked.

But now, November 2024, Comcast has apparently once again renumbered the network. freedns does not have the new address, but retains the address from September. I can reach a host inside the G34 local network (at a remote location) so I have discovered the newly assigned IP address from Comcast. But freedns does not have it, so DDNS updates are not arriving.

Is it possible the November 2023 firmware update which broke port forwarding has minimized DDNS updates in some way?

Please tell me how often DDNS updates are sent, after power up?