Can not play content with Dolby Vision

Whenever I’m trying to play content with Dolby Vision I get the audio, but not the visual. E.G. Fallout on Amazon Prime or any new Disney content. Other content works fine. If I play through HDMI it appears to work fine (I can only assume that the HDMI display aren’t dolby supported), but ideally I’d like to play natively through the app.

Any suggestions would be appreciated.