Task.Factory doesn't release memory?

Question

I use a Timer this way:

t = new Timer();
t.Interval = 10000;
t.Elapsed += ElapsedEvent;

and that's the ElapsedEvent method:

private void ElapsedEvent(object sender, ElapsedEventArgs e)
{
    t.Stop();

    try
    {
        var sessions = GetActiveSessions();

        foreach (var session in sessions)
        {
            Task.Factory.StartNew(() => MyProcessTask(session));
        }
    }
    catch (Exception ex)
    {

    }
    
    t.Start();
}

i.e. it will be executed every 10000ms.

But the memory in RAM is increasing, ever, and I need to restart the Windows Service (where this code is executed).

Is the way I use Task.Factory incorrect? Does the memory allocated by thread never be released by Garbage collector this way?