update and replace will erase the taxonomy paths

Hi there,
I've been using pathauto with the setting turned on for "Create a new alias, replacing the old one"

I have one vocabulary which must be manually set (because I use the [catalias] tag for all nodes which are members of a taxonomy residing in this vocabulary). So the setting field is blank for this vocabulary.

After editing a term in this vocabulary, PathAuto deletes the path altogether... It must be replacing it with nothing since "nothing" is entered into the setting field for that vocabulary.

Thanks for such a great module!