If overwriting a web layer immediately after it is published, it is possible that the browse dialog box needs to be refreshed to retrieve the latest portal items. If the web layer that is just published does not appear in the browse dialog box, try searching for the web layer name in the search box or hitting the refresh button.
At this time, only web feature layers (hosted) and map image layers can be overwritten from ArcGIS Pro. To overwrite a map image layer or a web feature layer published with the reference registered data option, search for the map image layer in the browse dialog box.
解决办法
Delete the existing service and publish the updated service to Portal for ArcGIS.