Log Level Severity in StackDriver

Hi I have Kong in GKE and applications are running fine I have kept my log level as debug. I am using Fluentd to extract my logs to ingest in stack driver. I notice the logs are written in the Stderr logs.
logname: projects/${project name}/logs/stderr which causing the log level to be captured as ERROR even the debug logs causing confusion in the metrics and alerts? I find this majorly in Kong-proxy Container.