Operations that use a pinned server don't properly clear the pinned server for retries because the pinned server is added directly to the driver.Operation. In order to fix this, we need to wrap the server selector in another server selector that will attempt to use a session's pinned server when server selection is taking place. An example of the fixed code can be found here: https://review.gerrithub.io/c/mongodb/mongo-go-driver/+/457635/6/mongo/session.go#192