I am trying to trigger another pipeline from my pipeline. it works fine if I don’t provide any pipeline_variables. However, If I provide any pipeline variable it fails with following error.

Error

 Failed to initiate a pipeline. API error code: 500. Message: {"code": 500, "message": "There was an error processing your request. It has been logged (ID db4257f76b7c00e8)."}

pipeline

    - step: &deploy_cloud_functions
        <<: [ *self-hosted, *base-img ]
        name: deploy_cloud_functions
        script:
          - pipe: atlassian/trigger-pipeline:5.7.0
            variables:
              BITBUCKET_USERNAME: $BITBUCKET_USERNAME
              BITBUCKET_APP_PASSWORD: $BITBUCKET_APP_PASSWORD
              REPOSITORY: 'deploy_cloud_functions'
              PIPELINE_VARIABLES: > 
                [{"file_name": "http_func_test.${BITBUCKET_BUILD_NUMBER}.zip}"}]

if I remove PIPELINE_VARIABLES from above this works without error.