not sure why exactly but it seems that a failed install might be the reason

what I did:

• QC detected Python 2 correctly
• I've added Python 3 (from Xcode11)
• created a python project
• switched to Python 3 for the project
• closed and re-opened the py file
• got informed QC found pip and can install pyls
  • hit the Install button
  • install failed - probably due to rights
  • tried to do it from command line (had to add --user to enforce install into the user directory instead of the global one)
  • returned to QC
• closed and re-opened the py file again
• got informed that QC found a pyls and could set it up
  • hit the Setup button
  • was happy that it worked

• when I closed QC it had a crash on exit..