ACME uses VPN interface instead of WAN when default gateway is set to WAN

[nheath]

Reading the docs about the default gateway setting ( c.f. https://docs.netgate.com/pfsense/en/latest/routing/gateways.html#managing-the-default-gateway ) it seems that ACME should use the WAN interface if I set the default gateway to WAN.

But ACME insists on using a VPN interface. Am I misunderstanding the documentation linked above?

Edit: The reason this is annoying is because the VPN ip address changes much more often than my WAN and I have to whitelist the IP used for for the API call by ACME to my DNS.