Bug? It appears the Social Media Vertical 9:16 Instagram Stories format does not work.
I started a new project with the Instagram movie profile and the export settings follow the vertical Instagram story ratio of 9:16 as set by the movie profile.
The video that is being processed has been shot in portrait mode. Windows Explorer states that width is 1080, height is 1920p.
Exported video's don't follow the 9:16 ratio but instead it is 1:1.