When I use the lock device and attach it to a door, the checkmark appears meaning that it detected the door. When I start the game, it works properly but, when I end the game and go back to edit mode, the lock device is red, meaning that it doesn’t detect the door. Because of that, when I start another game, the door can be opened.
Thank you for your report! We would like to look into this further, would you be able to submit a bug report using the form available here: Fortnite Creative
I’ve sent the report. Thanks.