Loki Promtail pipeline template cant find variables

I have following issue with loki promtail. Here is one configuration snippet from my promtail:

        pipeline_stages:
          - cri: {}
          - regex:
              expression: '^(?P<time>.*?)\|(?P<level>.*?)\|(?P<process>.*?)\|(?P<logger>.*?)\|(?P<thread>.*?)\|(?P<client>.*?)\|(?P<user>.*?)\|(?P<message>(?s:.*))$'
          - labels:
              level:
              logger:
              thread:
              client:
              user:
          - labeldrop:
              - filename
          - template:
              source: testo2
              template: '{{ .level }} - {{ .user }}'
          - output:
              source: testo2

I'm using the regex function to receive the required information. After it I create the labels. For the final message I would like to overwrite the output.

My example of the output message: INFO - testo

The problem occurs in the template function. The variables are empty. Normally I thought I can use from the regex/label value to parse the variable inside the template.

What I'm doing wrong?

Thanks in advance.

to get the value from the label, the following format is required:

{{`{{ .level }}`}}