Opentok chat is running slowly according I execute session.disconnect() and session.connect()

Question

I am new to the Opentok API and I am writing tests. In my tests I simulated disconnecting from the room and connecting again, but if I execute it at various times, the chat is runs slowly, until broken.

To init the chat I run $scope.initSession() and to disconnect I run $scope.disconnectFromSession().

I am using the Opentok.js version 2.13.2. See my following code:

var apiKey, sessionId, token;

apiKey = //my api key;
sessionId = //my sessionid;
token = //my token;

var session = null;
var publisher = null;
var stream = null;
var connectionCount = 0;
var publisherProperties = {frameRate: 7};

$scope.connected = false;

$scope.initSession = function() {
    if (OT.checkSystemRequirements() == 1) {
        // Initialize Session Object
        session = OT.initSession(apiKey, sessionId);

        createElement("publisher");
        // initialize a publisher
        publisher = OT.initPublisher('publisher', publisherProperties);

        session.on({
            streamCreated: function(event) {
                console.log("EVENT streamCreated: " + event.stream.name + " - " + event.reason);
                createElement("subscriber");
                stream = event.stream;
                session.subscribe(stream, 'subscriber');
            },
            streamDestroyed: function(event) {
                event.preventDefault();
                console.log("EVENT streamDestroyed: " + event.stream.name + " - " + event.reason);
                console.log('Stream ${event.stream.name} ended because ${event.reason}.');
            }                
        });
        connectToSession();
    } else {
        console.log('Browser haven´t support to WebRTC');
    }
}

function connectToSession() {
    session.connect(token, function(err) {
        if (err) {
            if (err.name === "OT_NOT_CONNECTED") {
                showMessage('Failed to connect. Please check your connection and try connecting again.');
            } else {
                showMessage('An unknown error occurred connecting. Please try again later.');
            }
        } else {
            // publish to the session
            session.publish(publisher);
            $scope.connected = true;
        }
    });
}

function createElement(id) {
    console.log(document.getElementById(id));
    if (document.getElementById(id) === null) {
        var divPublisher = document.createElement("div");
        divPublisher.setAttribute("id", id);
        document.getElementById("div-videos").appendChild(divPublisher);
    }
}

$scope.disconnectFromSession = function() {
    session.disconnect();
    $scope.connected = false;
    OT.off();
}

$scope.initSession();

I appreciate any help.