Issues with Talk server and High Performance Backend?

So I’ve set up an installation using the AIO setup. Everything works great except for when I want to use Talk. If I leave the High Performance Backend enabled, anyone connecting to an existing Talk session gets disconnected, I also see the following in the logs (which I don’t see if HPB is disabled):

[WARN] [2231063344122364] ICE failed for component 1 in stream 1, but we're still waiting for some info so we don't care... (trickle pending, answer received, alert not set)
[WARN] [2231063344122364] ICE failed for component 1 in stream 1, but we're still waiting for some info so we don't care... (trickle pending, answer received, alert not set)
[WARN] [2231063344122364] ICE failed for component 1 in stream 1, but we're still waiting for some info so we don't care... (trickle pending, answer received, alert not set)
[WARN] [2231063344122364] ICE failed for component 1 in stream 1, but we're still waiting for some info so we don't care... (trickle pending, answer received, alert not set)
[WARN] [2231063344122364] ICE failed for component 1 in stream 1, but we're still waiting for some info so we don't care... (trickle pending, answer received, alert not set)
[WARN] [2231063344122364] ICE failed for component 1 in stream 1, but we're still waiting for some info so we don't care... (trickle pending, answer received, alert not set)

If I disable the HPB, Talk works fine, no issues.

I’m suspecting it’s a networking issue though, potentially something with my setup which looks like this: Nextcloud is hosted in a Proxmox VM behind a firewall connected to the internet via Starlink. I run a Traefik proxy on a Digital Ocean droplet that proxies traffic to the Nextcloud server over Tailscale (the proxy and the NC server are on the same tailnet).

I followed this: all-in-one/reverse-proxy.md at main · nextcloud/all-in-one · GitHub to set up the proxy.

I also run a turn server (coturn) on the DO droplet.

So to summarise, everything in the admin console checks out, all green ticks, but when I enable that HPB, Talk stops working. I’ve searched for solutions but run out of channels to explore, I think I’m chasing the wrong problem. Still new to NC so looking for other potential channels to try or suggestions?