Crash when entering the Nether and End after entity goes through

Summary:
The game crashes when entering a nether portal after a certain amount of mobs have been sent through.

Steps to Reproduce:

1. Create a world.
2. Create a nether portal.
3. Enter the nether portal and come back to the Overworld.
4. Spawn 15 or more mobs and send them through the nether portal.
5. Enter the nether portal.

Observed Results:
The game crashes when entering the nether portal.

Expected Results:
The game should not crash when entering the nether portal.

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Original Description:
Game crashes to desktop upon entering the Nether. This has been happening consistently since the new beta release.

Edit: Seems to happen, in my case, after sending baby villagers to the Nether. The next time I try to enter, the game crashes to desktop. Then, when I reopen, I appear in the overworld about 10 blocks to the northeast. Always to the same position. The first time it happened, I loaded inside of solid blocks, and had to break my way out to avoid being suffocated. After several times of this happening, I was able to go to the Nether, as normal, only to discover that my baby villagers were nowhere to be found.