ionic build --prod -- -- --base-href /MyApp/ : why does my environment require extra, extra -- to build properly?

Why does my Visual Studio Code environment require an extra extra -- to get the base-href parameter to work for the ionic build command?

This unusual ionic build command works on my PC ...:
ionic build --prod -- -- --base-href /MyApp/

... it runs ...
> ng.cmd run app:build:production --base-href /MyApp/

If I run the normal build command ...:
ionic build --prod -- --base-href /MyApp/

... it is missing the --base-href parmeter...
> ng.cmd run app:build:production

My colleague's PC runs the normal build command and it works as usual ...:
ionic build --prod -- --base-href /MyApp/

... it runs ...
> ng.cmd run app:build:production --base-href /MyApp/

Possible Hint: our command line's syntax highlighting looks different too: My ionic build command changes "--prod -- -- --base-href" to dark grey. My colleague's only changes the extra "--" before --base-href to dark grey.

We have the same ionic versions installed:
> ionic info

Ionic:

Ionic CLI : 5.4.16 (C:\Users\MyUser\AppData\Roaming\npm\node_modules\ionic)
Ionic Framework : @ionic/angular 5.2.2
@angular-devkit/build-angular : 0.901.9
@angular-devkit/schematics : 9.1.9
@angular/cli : 9.1.9
@ionic/angular-toolkit : 2.3.3

Utility:

cordova-res : not installed
native-run : not installed

System:

NodeJS : v14.15.0 (C:\Program Files\nodejs\node.exe)
npm : 6.14.8
OS : Windows 10