No, it does go to gradations of ‘in between’; but if I put it on the very lowest setting that’s easy for me to look at, after ten minutes it goes off.
I guess the little turny-knobby thingie is very sensitive...
I see... Sounds like you have it figured right then. Sometimes they can change setting after they heat up just a bit. Electronics can have an operating temperature just like a car. Do you remember tubes? They wouldn’t even work as they were designed until they got warmed up to operating temp. :)