Updated field aliases do not change in the web map when a feature service is overwritten.
Last Published: January 15, 2016ArcGIS Online
Bug ID Number
October 20, 2015
August 21, 2020
After review by the development team, it has been determined that this issue is related to a known limitation with the software that lies outside of Esri's control. The issue's Additional Information section may contain further explanation.
The field alias stays because the pop-up saved in the web map uses the field alias "Change_this". The pop-up is automatically created when adding a feature service to the map.
Because the field alias can be changed to anything desired by the user when creating a pop-up, it is not recommended to change the alias saved on the pop-up automatically.
Remove the pop-up before saving the map. When opening the saved web map and add the pop-ups back, the alias is updated.
Remove the feature layer from the web map then re-add the layer to the same web map and the field name is changed.This is not the best workaround as pop-ups and styles must be reconfigured.