The url params are cleaned by the order they are in the request This gets rid of unneeded 301 redirects

core.php

	public function expected_url($path = '')
	{
		$path = empty($path) ? $this->phpbb_root_path : $path;
		$params = array();

		// Check the params by the order they are in the request
		foreach($this->request->variable_names(\phpbb\request\request_interface::GET) AS $get) {
			$def = $this->seo_opt['zero_dupe']['redir_def'][$get];
			if (($this->request->is_set($get, \phpbb\request\request_interface::GET) && $def['keep']) || !empty($def['force']))
			{
				$params[$get] = $def['val'];

				if (!empty($def['hash']))
				{
					$params['#'] = $def['hash'];
				}
			}
		}

		$this->page_url = append_sid($path . $this->seo_opt['req_file'] . '.' . $this->php_ext, $params, true, 0);

		return $this->page_url;
	}