I share the project tool as a tool in ArcGIS Enterprise, then I use it in ArcGIS Web AppBuilder as geoprocessing. I see that when I use the tool, it shifts the layer, but in ArcGIS Pro, it doesn't shift. What is the problem?
in ArcGIS Pro: (no shift)
in ArcGIS Web AppBuilder: (shift)
Pro uses the coordinate system of the first added layer. Anything added subsequently is projected-on-the-fly to match it. So depending on what you are adding and what its coordinate system is/was, you may or may not see a visual shift
Adding to what Dan has posted, the transformation used may also differ.