Logstash 5.6.1 inifinite loop? Encountered a retryable error

Here is an example of one of our filebeat prospectors. In case any shines any clues.

---
filebeat:
  prospectors:
    - input_type: log
      paths:
        - /var/log/app_name/web/*.log
        - /var/log/app_name/web/*.err
      encoding: plain
      fields:
        environment: production
        client: production
        product: app_name
        role: web
        team: undef
        log_type: rails
      fields_under_root: true
      document_type: app_name
      scan_frequency: 10s
      harvester_buffer_size: 16384
      max_bytes: 10485760


      tail_files: false

      # Experimental: If symlinks is enabled, symlinks are opened and harvested. The harvester is openening the
      # original for harvesting but will report the symlink name as source.
      #symlinks: false

      backoff: 1s
      max_backoff: 10s
      backoff_factor: 2

      # Experimental: Max number of harvesters that are started in parallel.
      # Default is 0 which means unlimited
      #harvester_limit: 0

      ### Harvester closing options

      # Close inactive closes the file handler after the predefined period.
      # The period starts when the last line of the file was, not the file ModTime.
      # Time strings like 2h (2 hours), 5m (5 minutes) can be used.
      close_inactive: 5m


      # Close renamed closes a file handler when the file is renamed or rotated.
      # Note: Potential data loss. Make sure to read and understand the docs for this option.
      close_renamed: false

      # When enabling this option, a file handler is closed immediately in case a file can't be found
      # any more. In case the file shows up again later, harvesting will continue at the last known position
      # after scan_frequency.
      close_removed: true

      # Closes the file handler as soon as the harvesters reaches the end of the file.
      # By default this option is disabled.
      # Note: Potential data loss. Make sure to read and understand the docs for this option.
      close_eof: false

      ### State options

      # Files for the modification data is older then clean_inactive the state from the registry is removed
      # By default this is disabled.
      clean_inactive: 0

      # Removes the state for file which cannot be found on disk anymore immediately
      clean_removed: true

      # Close timeout closes the harvester after the predefined time.
      # This is independent if the harvester did finish reading the file or not.
      # By default this option is disabled.
      # Note: Potential data loss. Make sure to