Well, I assume they were reinserted during the calling of FF and then CC again. As you know, CC requires FF to be closed so there must be quite a lot happening during the period the browser is called again.
I occasionally have a second look after CC'ing. Sometimes I'm able to push new and specific cookies over to the Wanted Screen in the hope nothing else is has been loaded in those short moments. Now I know that's not a totally safe method.