This read-only Counter64 counts the number of times this PM instance timed out waiting for hosts to reply with membership reports after a query. Admins use this to catch unresponsive or powered-off multicast receivers before the switch prunes them from the group and a subscriber notices the stream stop; because it is drawn from this instance's running statistics bin, it behaves like a long-running total rather than a rotating window, so admins baseline against it instead of expecting it to reset daily. On a residential VLAN used for multicast video delivery, a count of 300 over the current statistics window is the kind of number an admin would trend against the join/leave rate on the same port to judge whether it's normal channel-surfing or an anomaly worth a closer look.