This counter tracks frames dropped from the tail of the QoS shaper's queue because the queue was full when they arrived. A climbing value tells an admin the shaper's buffer is regularly overflowing, meaning offered traffic is exceeding the shaping rate and applications may be experiencing loss. For instance, if cmQosShaperStatsFTD spikes during a peak-hour period, the admin might raise the shaper's queue depth or rate to reduce the tail drops affecting a bursty stream.