Bumping this because I've hit another snag.

I've got three separate light control props for three different light areas, which is what I want. And for the most part, they work. They're set up so that by default, all the lights are on, and dialing them to 1 turns the lights off.

The problem is, once I dial them off, they won't turn back on if I dial them back to 0. Even CTRL+Z doesn't do the trick. I can't understand it.