This is not a substitute/equivalent for placing a workpage in two or more categories. This places a workpage not just in another composer category, but in a specific "subfolder" - the Collaborations subfolder/tab - of that category. If the workpage isn't a Collaborations page, don't use template CollabCat, just use "Category". Also: format--
CollabCat firstname(field) | lastname (not lastname | firstname).