Entities are disappearing again

Basically entities are disappearing again. This issue was reported back in version 15w32b (MC-85285) and was seemingly fixed by Searge in version 15w32c - https://twitter.com/seargedp/status/629692390547320835 - but as I started up a world in the new snapshot and I unloaded and reloaded a chunk with entities in it they vanished.