Running containers not detected correctly

I recently recognised an issue with one of the proxmox servers where openvz containers running on the host do not get recognised by the host node. Basically, if I perform vzlist, it shows them as running, but the proxmox web interface is showing them as offline. I have upgraded to the latest version of proxmox since I detected the problem, but it did not solve the issue.

Any help with this issue would be appreciated.