Check all remotes in the room, take out their batteries, look for remotes under cushions or books? Re-introduce them one at a time until you find the culprit. Then strum the buttons back and forth, up and down until you free the stuck key.
Edmund
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee.