Images aren't just under exposed, they have values of 0.0 even in exrs - enabling the Debug Settings and writing out all samples shows the GPU is actually rendering black.
1. Create a Level Sequence with a Cine Camera
2. Edit the Cine Camera properties to set the Exposure Method to Manual and adjust the Exposure Compensation until the scene is visible (+~8.0)
3. Set up a Camera Cut Track in Sequencer pointed to that Cine Camera
4. Add the sequence to Movie Render Queue
5. Set the output resolution for the job to 2048x1024
6. Add the Panoramic Render pass (needs the "Additional Movie Render Queue Passes" plugin enabled)
8. Resulting jpegs are black and have no image content
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-169865 in the post.