It is presented a method performed in a first radio base station, RBS, in communication with a radio network controller, RNC. The RNC is configured for multi-flow HSDPA, High-Speed Downlink Packet Access, operation and packet data units, PDUs, are communicated toward a user equipment, UE, node via the first RBS and at least one second RBS. The method comprises: detecting PDU drop events and/or loss events; and communicating information from the RBS to the RNC, notifying of each detected PDU drop event and/or loss event. A corresponding RBS and RNC are also presented.