End portal duplication glitch

You can duplicate blocks with gravity in this bug.

Steps to reproduce:
1. Activate an end portal
2. Place fences under the end portal
3. Place a block with gravity 6 blocks over the portal part of the end portal
4. Jump into the end portal
X. The item form of the block with gravity that fell into the end portal and the block form of the block with gravity that fell into the end portal will both be there