SFOS 18.0.0 EAP1-Refresh1 DDNS Fails on PPPoE Interface (DDNS update for host [DDNS Host] was Failed. Last Updated with IP 0.0.0.0. Failure Reason: noconnect)

When using DDNS via Namecheap on v18 EAP1-Refresh1 over a PPPoE Interface DDNS Fails to register with log entry as below

DDNS update for host [DDNS Host] was Failed. Last Updated with IP 0.0.0.0. Failure Reason: noconnect