Error when upgrading to Loki helm chart 6.27.0

[Tolsto]

Upgrading from Loki helm chart 6.26.0 to 6.27.0 results in error:

error while running post render on files: map[string]interface {}(nil): yaml: unmarshal errors: line 38: mapping key "my-label" already defined at line 37

This issue appears to arise when certain pod labels are unexpectedly duplicated in the rendered manifests. In my specific case, the labels under .Values.write.podLabels suddenly appear in all deployments and statefulsets because they are inadvertently leaked into .Values.loki.podLabels.
The root cause of this problem can be traced back to a change in #16062, which incorrectly utilizes the merge function. The merge function modifies the source object, which explains why the {{- with merge .Values.loki.podLabels .Values.write.podLabels }} block in templates/write/statefulset-write.yaml effectively merges the write pod labels into .Values.loki.podLabels, causing it to be mutated for subsequent accesses from other template files. For more information, refer to helm/helm#13308