That usually points to a permissions or mapping issue rather than the mount itself. Proxmox can see the NFS share just fine, but when you pass it through to the LXC, the container’s UID/GID often doesn’t match what the NFS server expects. The result is an empty (or inaccessible) directory.
I’d double‑check whether the container is unprivileged, look at the UID/GID mapping, and make sure the NFS export allows access from the container (root squash is a common gotcha). Once the IDs line up or you adjust the export options, the contents should show up.
