Note: I already solved this issue by forcing everything in “MGA2020-55_FME”, however the way FME writer handles GDA2020 data seems strange.

I am trying to update an “EPSG7855” table from SQL to an “EPSG7855” feature service in ArcGIS Online. 

After checking the log, FME seems do not think EPSG7855 is GDA2020 Zone 55 and trying to reproject the data. Which cause the GDA2020Zone55 layer not align with GDA2020 Zone 55 basemap.  

Log: 

2024-06-20 09:27:58|   0.9|  0.1|INFORM|The ESRIWKID number of the FME coordinate system 'MGA2020-55_FME' is '7855'
2024-06-20 09:27:58|   0.9|  0.0|INFORM|ArcGIS Online Feature Service Writer: Requesting metadata for Feature Service at 'https://services-ap1.arcgis.com/w6r4Ll*/arcgis/rest/services/Property/FeatureServer'
2024-06-20 09:27:58|   0.9|  0.0|INFORM|ArcGIS Online Feature Service Writer: Found layer/table 'property_view' with ID 4 for feature type 'property_view'
2024-06-20 09:27:58|   0.9|  0.0|INFORM|ArcGIS Online Feature Service Writer: Requesting metadata for layer/table 4 of Feature Service at 'https://services-ap1.arcgis.com/w6r4Ll*/arcgis/rest/services/Property/FeatureServer'
2024-06-20 09:27:58|   0.9|  0.0|WARN  |ArcGIS Online Feature Service Writer: Attribute 'pfi' on feature type 'property_view' has type 'esriFieldTypeString', but the type on the server is 'esriFieldTypeInteger'
2024-06-20 09:27:58|   0.9|  0.0|WARN  |ArcGIS Online Feature Service Writer: Attribute 'base_pfi' on feature type 'property_view' has type 'esriFieldTypeString', but the type on the server is 'esriFieldTypeInteger'
2024-06-20 09:27:58|   0.9|  0.0|WARN  |ArcGIS Online Feature Service Writer: Attribute 'centroid_pfi' on feature type 'property_view' has type 'esriFieldTypeString', but the type on the server is 'esriFieldTypeInteger'
2024-06-20 09:27:58|   0.9|  0.0|WARN  |ArcGIS Online Feature Service Writer: Attribute 'OBJECTID' on feature type 'property_view' is marked as read-only in the corresponding layer/table. Attribute values will be ignored
2024-06-20 09:27:58|   0.9|  0.0|WARN  |ArcGIS Online Feature Service Writer: Attribute 'SHAPE__Area' on feature type 'property_view' is marked as read-only in the corresponding layer/table. Attribute values will be ignored
2024-06-20 09:27:58|   0.9|  0.0|WARN  |ArcGIS Online Feature Service Writer: Attribute 'SHAPE__Length' on feature type 'property_view' is marked as read-only in the corresponding layer/table. Attribute values will be ignored
2024-06-20 09:27:58|   0.9|  0.0|INFORM|CS-MAP Reprojector: Transformation will be automatically selected for 'EPSG:7855' -> 'MGA2020-55_FME', and is not guaranteed to remain the same in future releases of FME
2024-06-20 09:27:58|   0.9|  0.0|INFORM|Reprojector: Using transformation `GDA94_to_GDA2020-7P,Inverse(Seven Parameter,EPSG:8048)' when reprojecting from EPSG:7855 to MGA2020-55_FME
2024-06-20 09:27:58|   0.9|  0.0|INFORM|Reprojector: Using transformation `GDA94_to_WGS84,Forward(Null,EPSG:1150)' when reprojecting from EPSG:7855 to MGA2020-55_FME

The “Name” and “Description” under “Coordinate System” is misleading as well.

“7Parameter” and “Conformal” should be transformations, it’s name shouldn’t be “EPSG7855”.