Error executing process > 'BWAMEM2_MEM (1)'

Caused by:
  No such variable: id -- Check script 'modules/local/bwamem2/main.nf' at line: 43


Source block:
  def prefix = task.ext.prefix ?: "${meta.id}"
  def ext = params.output_cram ? 'cram' : 'bam'
  """
  touch ${prefix}.${ext}
  
  cat <<-END_VERSIONS > versions.yml
  "${task.process}":
      bwamem2: 2.2.1
      samtools: 1.21
  END_VERSIONS
  """

Tip: you can try to figure out what's wrong by changing to the process work dir and showing the script file named `.command.sh`