Have you contacted Support about this issue yet? That’s the official way to report potential bugs and get official assistance. The community here is full of knowledgeable members that help users with questions, but with your descriptions, I’d say Support is the way to go to get this issued logged and possibly investigated.
Does this cutoff happen every time there is multiple detected events back to back? I wonder if a new event that follows a short event triggers a new motion warning there for cuts off the previous played message. To increase the length of events to minimize the previous, I’d up your motion sensitivity and okay around with the detection zone in hopes of longer events. Also, maybe playing with the physical aom of the camera may help also.