We are working to get this fixed and have an update coming very soon to correct this issue.
Until the issue is corrected, please use the following workaround.
When watching an episode press the "*" button on your Roku remote - the subtitle options for that episode should appear, and there you can select the second English subtitle option until our fix is released very soon. You will need to use this workaround for each episode you watch.
You can follow along the instructions as displayed on the video