Unknown App using Camera-- Troubleshooting

My phone was locked last night. I pushed the home button and saw the green dot (for video recording) in the top right corner. It disappeared. I opened the control center by swiping up from the bottom of the screen. There is a green circle with a white camera that says "Unknown, recently". See picture below. It looks like the FaceTime icon, however, when I actually tested FaceTime, the control center says "FaceTime, recently". I haven't been able to replicate "Unknown, recently" with any other app on my phone. Is there a way to see what app accessed my camera? Any other troubleshooting options?