Paige Chestnut

Yes, this is on a vanilla 1.9.2 server. Optifine is client side only.

Playing 1.9.2 (optifine) on a server. Dragon flew into gateway, a duplicate teleported. Proceeded to kill the dragon, next day someone traveling through the aforementioned gateway met the ghost dragon which had no boss bar. It tried to fly to the nest and got stuck in unloaded chunks. After bridging to free it, it flew back only to disappear again in seconds. It reappeared ~5 minutes later, which at that point admin butchered it.

this is happening to me as well, tested on several 1.8 worlds with both walking, running, and on horseback. i dont know if this bug affects cats as well, but assuming they use the same code for following/teleporting, it is likely.