The driver crashes with the following error:

An unhandled exception occurred and the process was terminated.
Application ID: Helios-6408e122-16e7-4b49-b613-826625892360
Process ID: 3620
Exception: System.ObjectDisposedException
Message: Cannot access a disposed object.
Object name: 'ClusterableServer'.

StackTrace: at MongoDB.Driver.Core.Servers.ClusterableServer.ThrowIfDisposed()
at MongoDB.Driver.Core.Servers.ClusterableServer.RequestHeartbeat()
at MongoDB.Driver.Core.Clusters.MultiServerCluster.RequestHeartbeat()
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.TimerQueueTimer.CallCallback()
at System.Threading.TimerQueueTimer.Fire()
at System.Threading.TimerQueue.FireNextTimers()

We are getting this error in our daily performance tests sometimes.
It happens at random times, not always at the same place.
Never with a direct call on the mongo driver (nothing from our code in the stacktrace).

We also run the same test on a single mongo instance. This never gives any problem.

When our framework starts in gets a client and database class.
It keeps using the same database class the whole time.