The Rocket Mount, a two-seater flying mount which is replacing the Zhevra mount as the Recruit-a-Friend bonus, is having its release delayed by an unspecified amount of time. We don't know why it's been pushed back, but nonetheless, it is.
Let's take this opportunity not to fall into the typical internet crying extravaganza that happens when something is delayed -- Blizzard did us all a favor by announcing a release date for something. Obviously they have a good reason to delay its publication, and we should be happy they're being honest about this.
The full blue statement is as follows:
While we had originally announced the new Recruit-A-Friend X-53 Touring Rocket reward would be coming in just a few short days, it turns out there are still a few bolts to tighten, some loose wires to tuck inconspicuously under the upholstery, and a handful of parts leftover that we're going to ponder and then assume we can safely throw away. As a result, we'll be releasing this beauty a bit later than we'd first anticipated. This will also give anyone interested in the current Zhevra mount reward some extra time to claim one. While we don't have an exact release date nailed down yet, we'll make an announcement once the new mount becomes available.