Mine are all good, a car I picked up for the granddaughter from a lady has bad lights, I gave her my kit I had bought and never used.
I will have to check if she did it yet, and tell her about the Off sounds strange .
I have often wondered about real bad ones, if you had them out and new ones on standby if you FU, scrape or sand smooth, and hit them with a good spreader tip on a torch and get them almost fluid with a quick pass.
I have done it with sheet plastics , Plexiglas and Lucite, smoothing cut edges.
The edge will be clear
there a fine point where you don't want to pass.