Websocket API: channel.session.reset - invalid topic

Hello all,

Not sure if this is the right place to post about this.

I'm writing a Websocket API client and am getting an error when I try to subscribe to the channel.session.reset topic. 

The response I get is this:

{
  id: 'blah',
  ts: 'blah',
  type: 'response',
  nonce: 'blah',
  error: 'err_bad_request',
  data: { message: 'invalid topic specified' }
}

Using the same code I have no problem subscribing to the channel.session.update topic:

{
  id: 'blah',
  ts: 'blah',
  type: 'response',
  nonce: 'blah',
  data: {
    message: 'successfully subscribed to topic',
    room: 'blah',
    topic: 'channel.session.update'
  }
}

So I believe my code is correct. (Quadruple checked the topic string in my code is correct as well.) 

Is there something I'm maybe missing, or could this be an API bug?

Thanks!