Upgrading app not updating configmap

I have a chart that includes lots of children charts.
One of those children charts creates a configmap.
It utilises a pre-install,pre-upgrade hook so that the configmap is created before all other charts are deployed.

The problem I am having now is that the configmap does not update when I upgrade the app in Rancher.

However, if I deploy my application with helm install and then use helm upgrade to upgrade it, I can see the configmap is successfully updated.

Anyone had similar experience or can explain the differences between deploying with CLI and deploying with Rancher?