AE not letting me reassign the / key to a custom shortcut. Why?

I'm wracking my brains to figure out what I'm doing wrong. But I can't understand why AE is not allowing me to choose my own custom keyboard shortcut for the "/" key. That is NOT one the keys you can't re-assign. So why isn't that possible? I'd like to assign the forward slash key (with no modifiers) "/" to "Fit" for the Composition Panel. What I don't understand is that I have another custom keyboard set where I managed to do that, see 2nd pic below. Why won't AE no longer let me reassign the / key? Has anyone else run into this issue. I already tried trashing preferences and that didn't help. I don't understand why I was able to assign that shortcut in one custom keyboard file and not in another.