Network Spikes in certain instances. Unplayable Maps

Certain instances randomly get these crazy network spikes that make them lag so bad it's unplayable. It's only that instance. Leaving the map fixes the issue. Reentering the map causes the lag again. Network will spike to 1500-12000 and just keep fluctuating, and the instance will never fix itself. Once this starts it's just a wasted instance or map. Logging out and back in or changing servers does nothing to fix this.