convulted when statement

when.yml

- name: Som action
  win_shell: blah blah
    when: '["C:\company\flag_files\", item.name, "-", item.cust_num, "-", release_version, "-", "installed.txt"]|join("") not in (env_flag_files.files|map(attribute="path")|list)'
    
    
## (env_flag_files.files|map(attribute="path")|list)' evals to 
  - C:\company\flag_files\test2-4321-5.2-installed.txt
  - C:\company\flag_files\test1-1234-5.2-installed.txt

## error output
The error was: template error while templating string: expected token ',', got 'installed'.