"Invisible" Dragon

So, I was just running Stone Vigil on my main character. Everything was fine until we got to the final boss of the dungeon Isgebind. The first time we fought the dragon I could see him perfectly fine, but after something happened and we wiped, weird things started happening. For one, when we returned to Isgebind for a second time, he was nowhere to be seen on my screen! I could target him, see the circular directional indicator that extends from his feet, I could see the orange AoE circles, I could see his health, but I could not see the dragon. This has happened to me on one occasion before and both times I managed to defeat the dragon despite its invisibility. Then, after the fight my game has crashed. Both times I've fought the "invisible" dragon my game has also crashed afterwords.
I hope this report helps A Realm Reborn become an even better game and that this bug gets squished underfoot!