3

Duplicate of MC-45512

Also see http://minecraft.gamepedia.com/The_Void for reference.

According to that, established behavior is for entities to disappear at Y=-64, not Y=-1. In fact, entities have not disappeared at y -1 since before 1.8 beta. Considering this also applies to players (even yourself, in third-person) as well as entities above y 255, and does not apply to particles and sounds created by these entities, it's really hard to call this new behavior "intended".