ddns: failing for cloudflare proxied DNS

Maintainer: @paper42
Environment: OpenWRT 22.02, Cloudflare Proxied DNS

Description: When using ddns-scripts to update a Cloudflare Proxied DNS record, it will successfully update the DNS record's IP address but because it is proxied, the public DNS record actually points to a Cloudflare-provided IP address. Because the DDNS Update Script checks against the DNS record to make sure it was successful, it sees the different IP address compared to what it thinks it should be and reports the update has failed, triggering it to retry again.

Perhaps an option to disable the post-update check?

205807       : Detect local IP on 'network'
 205808       : Local IP '51.***.***.***' detected on network 'wan'
 205808       : Update needed - L: '51.***.***.***' <> R: '104.***.***.***'
 205808       : parsing script '/usr/lib/ddns/update_cloudflare_com_v4.sh'
 205808       : Found Username 'Bearer' using Password as Bearer Authorization Token
 205808       : #> /usr/bin/curl -RsS -o /var/run/ddns/myddns_ipv4.dat --stderr /var/run/ddns/myddns_ipv4.err --noproxy '*' --header 'Authorization: Bearer ***PW***'  --header 'Content-Type: application/json'  --request GET 'https://api.cloudflare.com/client/v4/zones?name=my.TLD'
 205809       : #> /usr/bin/curl -RsS -o /var/run/ddns/myddns_ipv4.dat --stderr /var/run/ddns/myddns_ipv4.err --noproxy '*' --header 'Authorization: Bearer ***PW***'  --header 'Content-Type: application/json'  --request GET 'https://api.cloudflare.com/client/v4/zones/***/dns_records?name=my.TLD&type=A'
 205811       : IPv4 at CloudFlare.com already up to date
 205811  info : Update successful - IP '51.***.***.***' send
 205811  info : Forced update successful - IP: '51.***.***.***' send
 205811       : Waiting 600 seconds (Check Interval)
 210811       : Detect registered/public IP
 210811       : #> /usr/bin/host -t A my.TLD >/var/run/ddns/myddns_ipv4.dat 2>/var/run/ddns/myddns_ipv4.err
 210812       : Registered IP '104.***.***.***' detected
 210812  WARN : Updating IP at DDNS provider failed - starting retry 31/0

Start with the ddns-scripts Cloudflare path, especially /usr/lib/ddns/update_cloudflare_com_v4.sh, and reproduce the behavior using a proxied Cloudflare DNS record. Trace the post-update comparison shown in the logs and determine how completion should be recognized when the public record returns a Cloudflare IP. Done means the successful provider update no longer triggers repeated retries in this environment.