https://github.com/Microsoft/MRDesignLabs_Unity_Tools/blob/ec32b17034e2950784d084f838bd2b858bdc7b23/HUX/Editor/Utility/HUXEditorUtils.cs#L236-L267
If the component type that SceneObjectField is looking for is present twice on the same object, the dropdown/popup portion of this field implementation fails and will always select the first of the two components.
This appears to be an issue with EditorGUILayout.Popup(selectedIndex, displayedOptions) ignoring duplicate entries. Solution would be to include a unique component to the string in displayedOptions, such as the index of the entry so there is never a duplicate string.