Meeting-efficiency consultants recommend agendas, timeboxes and a standing rule that anything over thirty minutes is a workshop.
Timebox from your end. Arrive at :50, apologise briskly, and enjoy a ten-minute meeting in which the decisions are made and nobody expects you to have context. Field notes: the Monday hour compressed to ten minutes for eleven consecutive weeks. In week twelve it was quietly rescheduled to start at :50, and you arrived at :40 the following hour.