Hi, @JLegendre8 
I found a resource internally and got our answer.
This is working as designed. The issue is due to the endpoint predating the release of branches in workflows. There isn’t a way to force the endpoint to return multiple branches or coerce that data from another of the existing endpoints for Workflows.
I don’t have a roadmap or date to share, but my suggestion is make sure you’re subscribed to the HubSpot Developer Changelog so you are the first to know when the revamped endpoints get released publicly.
Best,
Jaycee