That is interesting, I would think that if you remove the params from the single page app, publish and save that so that the params no longer appear, then go in import it to a multipage app they should not be 'following' into the multipage app
You may need to delete that page from the multipage app and try 'creating' the page natively inside the multipage app with some copy/pasting of components and queries over if the ghost params are still there after deleting the imported page