Did the VM that was running rancher/server reboot?
Typically, I’ve seen this happen when the VM reboots and you hadn’t deleted your previous running rancher/server container. Since rancher/server is started with
--restart=always, it will pick the first container that was launched (probably v0.51.0).
All you need to do is stop the rancher/server:v0.51.0 container and start up the v1.0.1 container.
Did you create a data container when upgrading? If so, you should be able to remove the old container to prevent this from happening again.