Issue with persistent sessions using auth0-js and SAML


I am having some issues with persistent sessions when using auth0-js.
We are are setting up as follows:

new auth0.WebAuth({
      clientID: this.auth0Config.clientID,
      domain: this.auth0Config.domain,
      responseType: 'token id_token',
      redirectUri: window.location.origin + '/callback',
      useRefreshTokens: true

and then log in as follows

      organization: this.auth0Config.organization,
      connection: this.auth0Config.connection.toLowerCase()

When we then go to initiate our single sign on through SAML we get prompted to re-authenticate. The desired behavior is that we are not prompted to log back in.

We are initiating the SAML login via the domain/samlp/{clientId}

Any pointers would be appreciated, thank you.