Yes - make sure that your default NZB folder is not the same as your autoimport folder, or you'll get this type of infinite loop.
e.g. RSS adds something to queue and saves NZB to default folder ... as this folder is also the autoimport folder, after a certain time it will be added again to queue ... and since autoimported NZBs are moved to default NZB folder, it gets imported again, etc. etc.