These are flows that the PacketShaper marked as TCP half disconnect. You can also consider this state the same as a TCP half-open state where (according to RFC 793) Host A on one end has not been notified that the other end (Host B) has closed the session. The flow is now in an Idle state which can last for an unbounded period of time.
When the flow is in this state, the PacketShaper will consider it an Idle Connection and it will stay in this state for up to 24 hours. After this time, it will be flushed.