The data aggregation boundary generalizations were improved in the October 2023 product release of ArcGIS Business Analyst Web App. In addition, new options were added in Preferences > General > 'Data aggregation' to specify the level of detail. Now, there is a setting to how much the polygon boundaries will be generalized. These enhancements should have improved the reported drive time generalization issue.
解决办法
Create the Drive Time area in an ArcGIS Online web map, and add the layer into ArcGIS Business Analyst Web App if required.
In ArcGIS Business Analyst Web App, click 'Add data' > 'Web maps and layers' and add the previously created layer.