IPv6 packet loss with custom br0 network, but not with the bridge network

I moved my smokeping docker container from my bridge network to my custom br0 network. However, once I did that, all my targets connecting via IPv6 are getting packet loss. Here's an example (anything that isn't green is when I get packet loss and the container is on the br0 network):

When I run a ping from within that container, I'm always getting packet loss when I run the command forcing IPv6. I don't get any packet loss on IPv4:

80c35650254d:/config# ping -4 -c 5 google.com
PING google.com (142.251.40.46): 56 data bytes
64 bytes from 142.251.40.46: seq=0 ttl=118 time=1.429 ms
64 bytes from 142.251.40.46: seq=1 ttl=118 time=1.337 ms
64 bytes from 142.251.40.46: seq=2 ttl=118 time=1.262 ms
64 bytes from 142.251.40.46: seq=3 ttl=118 time=1.401 ms
64 bytes from 142.251.40.46: seq=4 ttl=118 time=1.400 ms

--- google.com ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max = 1.262/1.365/1.429 ms
80c35650254d:/config# ping -6 -c 5 google.com
PING google.com (2607:f8b0:4007:819::200e): 56 data bytes
64 bytes from 2607:f8b0:4007:819::200e: seq=0 ttl=117 time=1.918 ms
64 bytes from 2607:f8b0:4007:819::200e: seq=2 ttl=117 time=1.812 ms
64 bytes from 2607:f8b0:4007:819::200e: seq=3 ttl=117 time=1.952 ms
64 bytes from 2607:f8b0:4007:819::200e: seq=4 ttl=117 time=1.884 ms

--- google.com ping statistics ---
5 packets transmitted, 4 packets received, 20% packet loss
round-trip min/avg/max = 1.812/1.891/1.952 ms

I monitor sites like google.com using smokeping, but I also monitor IP addresses like Quad9's DNS servers. With IP addresses, I'm not seeing any packet loss when testing the IPv4 9.9.9.9:

But I am seeing packet loss when I test Quad 9's IPv6 DNS servers:

So my issue is that any outbound connection to an IPv6 address is always getting some packet loss when in my custom br0 mode. Any ideas on what I should look into?

I'm on the latest unRAID 6.12.9. I'm using pfSense are my gateway, and IPv6 is handled via SLAAC.

Here are my interface settings:

Here is my routing table:

Here are my docker settings: