Thanks for the prompt feedback but the wiki states: "The forward-slash escape character / disables the special meaning of the character that follows it." Another idea?
Have you tried it without the slashes? To be clear, I'm not on a Mac (I'm on Linux), but when I try entering your string into the "Rename Move Replace" dialog it seems to be parsing the forward slashes as indicating an additional subdirectory rather than as escape characters (it's using the [album] portion to create another layer of subdirectories). When I enter "=[album] (24-96)" in the file window (no quotes), I get the correct result.
The wiki says that "To use a literal parenthesis, comma, or whitespace
inside of function argument lists, escape them [emphasis added]"; this context is not a function argument list so perhaps it needs no escaping.
You can see how the rename tool will parse your expression before commiting by looking at the "new" column in the option window.