If a Portal for ArcGIS site map units are set to metric and a user accesses the ArcGIS Web AppBuilder app anonymously, the app's scale bar units are miles and do not take into account the map unit setting.

Solução Provisória

Follow the steps below when creating the web app.

1. Under Widgets, open the Scalebar widget.
2. Do not make any changes (unless desired), and click OK.
3. Save the app.

This process updates the JSON for the widget to include the scalebarUnit.

Etapas para Reproduzir