Docker Container on IPVLAN Can't Access Gateway

I am running docker on an Ubuntu host. The host has full internet connectivity from the firewall router. I have some containers running on IPVLANs 20 and 21 attached to host eth0 as the parent. Containers in the same VLAN can talk to each other, however neither can reach it’s gateway on the firewall router.

Creating a VLAN on eth0 using netplan on Ubuntu, I can attach a VM to it and it receives an IP via DHCP from the router and can access the internet. This leads to me believe I am doing something wrong with docker networking.

This is my network diagram:

I used the following command to create the network:

docker network create -d ipvlan --subnet=10.1.20.0/24 --gateway=10.1.20.1 -o parent=eth0.20 ipvlan20