QFQ complains that the given SIP parameter is already defined. Problem is the pre filling of Store SIP, which normally happens only during form load. But the new 'saving a new record (r=0) and redirecting the browser to the same page with the new record id', requires a new SIP. That SIP is calculated before form-load and causes the exception. Fix: defined parameter in a store, which will be redefined with the same value, wont' throw an exception anymore.
Store.php: compare old and new value and only if they differ throw an exception.