If the connection is triggered immediately, an infinite recursion might occur. This is caused for example by an invalid TLS client certificate (i.e. invalid content) that can be specified via the tlsClientCertificateFile option during MongoClient.connect.

The recursion occurs due to the order of operations in connectServers (https://github.com/mongodb/node-mongodb-native/blob/master/src/sdam/topology.ts#L824). The server is connected to before it is added to the internal known server descriptions. An invalid TLS certificate file however causes an immediate error in server.connect() (https://github.com/mongodb/node-mongodb-native/blob/master/src/sdam/topology.ts#L810). This error is caught and tried to react synchronously in an event listener which tries to access the known server descriptions - which have not been updated yet.