Sounds like your scene is looping. Have you put the scene to loop once?
ADJ won't let us create scenes that do not loop because "its designed that way......."
What you have to do is create a blackout scene, then make it fade in, and just make the wait time on the second/last step really long, like an hour or...ten.. (EDIT: You have to repeat the last step X times if you want it to stay for more then 43 minutes.)
I also have the same problem, i have set key 1 on my keyboard to a "blinder" effect i created, so when i press 1 it will quickly go from blackout to bright white (.480 sec) to give the audience a "blinder" feeling-ish (because i don't have any blinders yet.)then quickly press another keybind to run another scene.
If i don't set the last step to last really long, it will run the blinder scene a second time and (in my eyes)damaging the light show completely.