I have noticed the last week or two when I fly out of Stormwind towards Karazhan I will sometimes disconnect or be unable to use Dragonriding abilities for a bit around the time I hit Duskwood.
In this case, I flew to the ground and manually dismounted but kept moving at mount speed (unable to fly) and then after about a minute was teleported back to the edge of Duskwood high in the air. I proceeded to fall to the ground, dying on the edge of the river as my character was swimming through the air. During this minute I was able to type in general chat and multiple people replied, stating they were also getting disconnected flying into Duskwood.
PS - The bug report system is awkward, if you follow the in-game prompts through support it says to “please use the provided in-game systems to notify our development team directly.” There’s a Report a bug button that when clicked, takes you to battle.net support site. So I’m making this in the hopes that this is the correct way of reporting something like this.