Flask - Invalid input argument received TERMINATING pipeline

I'm having problems with Flask running in a python virtual environment:

My app runs just fine when I enter:

> flask run

When I check the version I get what you would expect:

> flask --version Python 3.12.3 Flask 3.0.3 Werkzeug 3.0.3 

However, I get an error message trying to launch flask shell:

> flask shell>>> Invalid input argument: >shell< received  TERMINATING  pipeline!

I get the same invalid input argument error message for:

> flask db>>> Invalid input argument: >db< received  TERMINATING  pipeline!> flask --help>>> Invalid input argument: >--help< received  TERMINATING  pipeline!> flask routes>>> Invalid input argument: >routes< received  TERMINATING  pipeline!

I've tried reinstalling the same python 3.12.3 venv, as well as python 3.8.3, 3.6.8 venv as well as on different projects with the same results.

I'm running it in a Powershell terminal in VSCode.

Any ideas would be welcome.