When the content is started via deeplink, does the content play without user interaction?
Have you checked with http://devtools.web.roku.com/DeepLinkingTester/
Are you sure you have deeplink content items correctly set up in the dev portal deep link section?
https://developer.roku.com/developer-channels/channels/edit/deepLinking/<yourChannelId>
If deeplink is set up correctly and content is playing, It may be that the automated test device has issues. Reupload and test again. Sometimes it just fails...