Item Multiplication in Hopper Clock

When entering the Nether, the items in a hopper clock located there, get multiplicated.

To replicate:

• Build a hopper clock in the Nether.
• Put around 100 villagers near the clock.
• Exit and enter in the Nether through the Nether Portal.
• There are more items in the hoppers than before.

I give you a map where you can easily test this. Simply exit and then enter the Nether and you'll see that you have more items in the hoppers.