Rename issue - Is this a bug?

My new rule is looking for files where kind is Movie. It then renames with pattern 'name extension'. For name I've selected Replace Text in the name bubble, and I want to replace all periods with a space. So "My.File.mp4" becomes "My File.mp4".
I can set name to Title Case, UPPERCASE, lowercase, etc, and that DOES work. But the text substitution doesn't. I've tried other substitutions (= for G, z for f, etc).
Am I missing something?
btw - I assume the period in the file extension isn't considered part of the 'name', but that doesn't seem to be an issue at the moment.
I can set name to Title Case, UPPERCASE, lowercase, etc, and that DOES work. But the text substitution doesn't. I've tried other substitutions (= for G, z for f, etc).
Am I missing something?

btw - I assume the period in the file extension isn't considered part of the 'name', but that doesn't seem to be an issue at the moment.