Gateway Monitoring not working on 21.1.5

[sudo rm -rf]

If I enable Gateway Monitoring on my IPv6 gateway and enter an IP, dpinger says it fails to connect (sendto error: 65).  However, if I drop to shell and run the dpinger command directly, it works.

If I can run dpinger on the router, why does the Gateway Monitor dpinger fail?  It constantly reports 100% loss and flags the gateway as down, even though it clearly is up and working fine.  I've tried several other IPs (like  2001:4860:4860::8888) and all of them produce the same broken result.