So a new development! I attempted to add the HD video feed to the Pocketcasts web player and it displayed that the 'Show is on break of finsihed'. That tells me it's not accepting the api key. Sounds like a bug to me but I'm not sure if it's a bug on their side or on GB's side. Should I file a bug report here on GB?
In the mean time I've installed PodcastAddict on my phone and the video feed works fine there.