I found an alternative way to delete scenes in the Alexa app . . .
You would need to add the scene to a Group, then delete it from there.
Open the Alexa App.
Select Devices, then select a Group and hit "Edit" in the top right corner.
Scroll all the way down and add these extra Scenes to the Group and save.
While looking at the Group, scroll down and tap on the Scene and then you'll see the trash can icon to delete it.
Not elegant, but it works
