helm upgrade with --reset-then-reuse-values flag restarts all pods

[madhugarimilla]

With 'helm upgrade' command , only the pods with the modified deployment.yaml files used to restart but with 'helm upgrade --reset-then-reuse-values' it restarts all the pods no matter whether it's deployment is modified or not. Is this a expected behavior or a bug?

Output of helm version:
version.BuildInfo{Version:"v3.14.4", GitCommit:"81c902a123462fd4052bc5e9aa9c513c4c8fc142", GitTreeState:"clean", GoVersion:"go1.21.9"}

Output of kubectl version:
WARNING: This version information is deprecated and will be replaced with the output from kubectl version --short. Use --output=yaml|json to get the full version.
Client Version: version.Info{Major:"1", Minor:"25", GitVersion:"v1.25.3", GitCommit:"434bfd82814af038ad94d62ebe59b133fcb50506", GitTreeState:"clean", BuildDate:"2022-10-12T10:57:26Z", GoVersion:"go1.19.2", Compiler:"gc", Platform:"linux/amd64"}
Kustomize Version: v4.5.7
Server Version: version.Info{Major:"1", Minor:"27", GitVersion:"v1.27.11-gke.1062001", GitCommit:"2cefeadcb4ec7d21d775d15012b02d3393a53548", GitTreeState:"clean", BuildDate:"2024-04-16T20:17:53Z", GoVersion:"go1.21.7 X:boringcrypto", Compiler:"gc", Platform:"linux/amd64"}
WARNING: version difference between client (1.25) and server (1.27) exceeds the supported minor version skew of +/-1

Cloud Provider/Platform (AKS, GKE, Minikube etc.):
GKE

[gjenkins8]

Helm is just updating the deployment object as instructed by the chart rendered from the input values

The deployment is what is restarting the pods. You may be able to identity what is being changed, and why this is causing the deployment to recreate pods with e.g. kubectl rollout history ...