There are not <BrowserRouter> in pluggable widget’s XML.
Learn more before build pluggable widget,please.
https://docs.mendix.com/howto/extensibility/pluggable-widgets
https://docs.mendix.com/apidocs-mxsdk/apidocs/pluggable-widgets
https://docs.mendix.com/apidocs-mxsdk/apidocs/pluggable-widgets-property-types