admission webhook "sidecar-injector.istio.io" denied the request: failed to run injection template: template: inject:54:74: executing "inject" at <.Release.Namespace>: can''t evaluate field Release in type *inject.SidecarTemplateData

.Release.Namespace is not set in the params used when processing the injection template. See here.

The injection template also sets the fsGroup to 1337, but should use .ProxyGID.