Hi Patrick, let’s work through this!
The Shotgun Fields are only available through the Mu-based shotgun integration (called Shotgun Integration and Screening Room). The following suggests to me that you probably have the Shotgun Review package enabled on your Shotgun site:
If you want to utilize Screening Room/Shotgun Integration (such as you sessionFromVersionID is doing), you want to disable Shotgun Review on your site. Note that this is a global change and will change the links that are generated for everyone on your site.
The responsible site preference should look like this to disable Shotgun Review (in favor of Shotgun Integration/Screening Room):
Once you do that, a similar link will be generated for your Play in RV.
As far as the fields for the track.info on each source, they aren’t created immediately. They are created asynchronously slightly after the source is created. If you are trying to access them on source-group-complete, it will be too soon for the API query to have filled out the data. Instead, watch for graph-state-change where tracking.info is in the event.contents().
@jacobg was recently doing similar work over here and shared his function to achieve something similar.
RV Screening Room read version data - #9 by jacobg