single vlan not getting passed to guests

As the title says.
I currently have 2 working network devices going to a VM (ID 101):
net0 on vmbr0, vlan 20 -- the main link, works fine
net1 on vmbr1 -- private link between VMs, works fine

My problem comes when I create the next link:
net2 on vmbr0, vlan 30 -- I can set the ip address (10.30.1.252/29) within the guest, and it can ping itself fine

On the Proxmox host, I have the two link devices connecting the guest to the bridge:
# ip link show up |grep vmbr0
45: fwpr101p0@fwln101i0...

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