请问楼主的这个问题有解决吗？我也遇到同样的问题，不知道什么原因。
//微信单次分账支付, $receive 分账接收方列表
public function wechat_profitsharing_buid($params, $wechat,$receive){
		global $_W;
		load()->func("communication");
		$wOpt = array( );
		$package = array( );
		// $platform_amount = ($params['fee'] - array_sum(array_column($receive, 'amount')));//平台分成 = 订单总金额 - 分给接收方的分成
		// $platform = array('type'=>'MERCHANT_ID','account'=>$wechat["mch_id"],'amount'=>$platform_amount,'description'=>'分给平台');//平台
		$package["mch_id"] = trim($wechat["mch_id"]);//商户号
		$package["appid"] = trim($wechat["appid"]);//公众账号ID
		$package["nonce_str"] = random(32);//32位随机字符串
		$package["transaction_id"] = $params['transaction_id'];//微信支付订单号
		$package["out_order_no"] = trim($params["tid"]);//商户分账单号
		$package['receivers']=json_encode(array($receive));//接收会员列表，包含字段：type、account、amount、description
		ksort($package, SORT_STRING);
		$string1 = "";
		foreach( $package as $key => $v ) 
		{
			if( empty($v) ) 
			{
				continue;
			}
			$string1 .= (string) $key . "=" . $v . "&";
		}
		$string1 .= "key=" . $wechat["apikey"];
		$package['sign_type'] = 'HMAC-SHA256';//签名类型，目前只支持HMAC-SHA256
		$package["sign"] = strtoupper(hash_hmac('sha256',trim($string1),$wechat["apikey"]));//sha256签名，
		flog($package,'common.wechat_profitsharing_buid.log','ewei_shop.model','package封装请求的参数');
		$dat = array2xml($package);
		$response = ihttp_request("https://api.mch.weixin.qq.com/secapi/pay/profitsharing", $dat);
		
		flog($response,'common.wechat_profitsharing_buid.log','ewei_shop.model','RESPONSE的值');
		if( is_error($response) ) 
		{
			return $response;
		}
		libxml_disable_entity_loader(true);
		$xml = @simplexml_load_string(@trim($response["content"]), "SimpleXMLElement", LIBXML_NOCDATA);
		if( strval($xml->return_code) == "FAIL" ) 
		{
			return error(-1, strval($xml->return_msg));
		}
		if( strval($xml->result_code) == "FAIL" ) 
		{
			return error(-1, strval($xml->err_code) . ": " . strval($xml->err_code_des));
		}
		$prepayid = $xml->prepay_id;
		$wOpt["appId"] = trim($wechat["appid"]);
		$wOpt["timeStamp"] = TIMESTAMP . "";
		$wOpt["nonceStr"] = random(32);
		$wOpt["package"] = "prepay_id=" . $prepayid;
		$wOpt["signType"] = "MD5";
		ksort($wOpt, SORT_STRING);
		$string = "";
		foreach( $wOpt as $key => $v ) 
		{
			$string .= (string) $key . "=" . $v . "&";
		}
		$string .= "key=" . $wechat["apikey"];
		$wOpt["paySign"] = strtoupper(md5(trim($string)));
		return $wOpt;
}

这应该是你本地代码的问题。不是接口的错误。请仔细核对检查代码