CWL capture multiple output files with prefix

I have a CommandLineTool demo, and run as:
demo –AA file1.txt –BB file2.txt –CC file3.txt –nthreads 4
input file: –AA
output file： –BB –CC

The fllowing CWL doesn’t work.

error:

(“Error collecting output for parameter ‘ofile1’:ndemo.cwl:32:7: Did not find output file with glob pattern: ‘[‘file2.txt’]'”, {})

Why?

Thanks in advance.

cwlVersion: v1.0
class: CommandLineTool
baseCommand: demo
inputs:
  infile:
    type: File
    inputBinding:
      prefix: --AA
      position: 1
  outfile1:
    type: string 
    inputBinding:
      prefix: --BB
      position: 2
  outfile2:
    type: string 
    inputBinding:
      prefix: --CC
      position: 3
  nthreads:
    type: int
    inputBinding:
      prefix: --nthreads
outputs:
  ofile1:
    type: File
    outputBinding:
      glob: $(inputs.outfile1) 
  ofile2:
    type: File
    outputBinding:
      glob: $(inputs.outfile2)