This issue is not reproducible in ArcGIS Online. If the issue persists, contact Esri Support Services as additional information is required for further investigation.
解决办法
Change the map to the WGS 84 coordinate system when publishing in ArcGIS Pro to transform the data to the WGS 84 coordinate system rather than on the fly in the Portal for ArcGIS.
Change the transformation to another supported transformation when publishing from ArcGIS Pro.
Use a basemap that is projected in the GDA2020 coordinate system so that the data is not projected on the fly.