I am developing a suite of geoprocessing tools in Python in the new ArcPro 3.0.1 toolbox (atbx). One of my parameters is a multivalue parameter of fields which is dependent upon a previous parameter selection (the layer the fields are coming from).

This creates the desired ability to choose one or more fields from the layer. But during testing I have noticed an odd behaviour which I don't want and am unsure if this a property that can be fixed through coding or its a bug, or (unwanted) behaviour baked in by esri?
So.. If I run the tool, set the layer, I can choose my fields; if I select them via the drop down then they are displayed in order as they are in the attribute table as shown below:

The fields are displaying in the order as they are found in the attribute table (i.e. unsorted)
But if I use the add many fields button the list is displayed in name sort order as shown below:

Fields in drop down are presented in name sort order
How do I stop/correct it from sorting by name order?