mongoose: Don't reconnect after disconnection

After upgrading from 4.4.11 to >=4.6.1 we get random disconnections and mongoose never reconnects.

mongoose version: 4.6.5 mongodb version: 3.2.9

This is the way I create the connections:

    var uri = 'mongodb://USENAME:PASSWORD@host1:port1,host2:port2/database?authSource=admin';

    var options = {};
    options.server = {
      auto_reconnect: true,
      poolSize: 5,
      socketOptions: { keepAlive: 1, connectTimeoutMS: 30000 },
      reconnectTries: 3000
    };

    options.replset = {
      auto_reconnect: true,
      poolSize: 5,
      socketOptions: { keepAlive: 1, connectTimeoutMS: 30000 },
      reconnectTries: 3000
    };

    var db = mongoose.createConnection(uri, options);

    mongoose.connection.on('error', function(err) {
      console.log('MONGODB ERROR MONGOOSE LEVEL ' + server, err);
    });

    db.on('connecting', function() {
      console.info('MONGODB ' + server + ' connecting.');
    });

    db.on('error', function(err) {
      console.log('MONGODB ERROR ' + server, err);
    });

    db.on('close', function(err) {
      console.log('MONGODB CLOSE ' + server, err);
    });

    db.on('connected', function() {
      console.info('MONGODB ' + server + ' connected successfully.');
    });

    db.once('open', function callback() {
      console.info('MONGODB ' + server + ' opened successfully.');
    });

    db.on('reconnected', function() {
      console.info('MONGODB ' + server + ' reconnected.');
    });

    db.on('timeout', function() {
      console.info('MONGODB ' + server + ' timeout.');
    });

    db.on('disconnected', function() {
      console.info('MONGODB ' + server + ' disconnected');
    });

This is the sequence of events I get:

pid:3429 MONGODB geo_uri connected successfully.
pid:3429 MONGODB geo_uri opened successfully.
pid:3429 MONGODB dashboards_db connected successfully.
pid:3429 MONGODB dashboards_db opened successfully.
pid:3429 MONGODB tweet_analytics_db connected successfully.
pid:3429 MONGODB tweet_analytics_db opened successfully.
pid:3429 MONGODB fullcontact_enrichment_db disconnected
pid:3429 MONGODB ERROR fullcontact_enrichment_db { [MongoError: no valid replicaset members found]
  name: 'MongoError',
  message: 'no valid replicaset members found' }
pid:3429 MONGODB uri connected successfully.
pid:3429 MONGODB uri opened successfully.
pid:3429 MONGODB sync_reports_db connected successfully.
pid:3429 MONGODB sync_reports_db opened successfully.
pid:3429 MONGODB uri disconnected
pid:3429 MONGODB CLOSE uri

Then none of the disconnected databases reconnect. Due to the random nature of the problem, I won’t be able to provide a code to reproduce it. I suspect about something saturated at node.js level or so. Independently of the cause of the disconnection, is there anything I can do to try to reconnect myself?