^{Update by LateLag:}
Steps to Reproduce:

1. Enter a Nether Portal;
2. Once you've been teleported, drop an item without moving out of the portal;
3. Return to the original dimension;
4. If the bug is not triggered, try again.

Observed Results:
The dropped item disappears and can't be recovered.**

Expected Results:
The item appears on the other side.**

Screenshots/Videos attached: No

Notes: Any item can be affected by this issue, not only enchanted ones.

Original Description:

I was playing the game normally when I accidentally threw my Diamond Sword throught a Nether Portal, and when I travelled throught the Portal, the Sword Disappeared. I travelled back and nothing changed. Lost my sword. There was a Villager in the Nether right in the Portal, but as far as i know, Villagers can't take Swords.

I don't now if this makes any difference, but the Sword was with a Custom Name; Mending; Fire Aspect II; Unbreaking III; Sharpness V; and Looting III.