Items Disappearing

Me and DemonThunder were out one day when we were killed by Enraged Zombies and Enraged Creepers. None of us lost anything though.

All I get is golden apples from Enraged Creepers.

I'll experiment with Enraged Zombies tomorrow and gather results about the possible buggyness of the canpickuploot variable that mobs have.

You're a braver penguin than I.
Good way to get rid of unwanted residence dirt though, I suppose.

I'm just going to throw dirt at mobs, then change to singleplayer.

I think aikar set mobs to not pick up loot. There may be a bug with this. I think the zombies are picking up the items and then the game is realizing they can't pick up loot so it despawns. Also, mobs with name tags MAY keep the chunk loaded so the items would despawn. How close were you to your death point?

In all three instances, Wasteland -> Town.

-When adventuring with lehmaqr, he attempted to locate my remains (well within 5 minutes) and was unable to do so despite being at the coordinates. (And yes, I trust him to have returned anything if he had found my items).
-The other two times involving the Momentus, lotayx and BadgersOnTop were present in the area, but I was again able to return to my point of death well within the 5-minute mark. The second time I died, I watched through the death screen as my items simply vanished. I saw them on the ground, and then an instant later, they were all gone. Armor, potions, water buckets, weapons & arrows, etc, and the Enraged Zombie passed directly through that space a second afterwards. That was the basis of my "vaccuum cleaner" theory before, which you more or less reiterated.

I can say with certainty however that the items were not taken by players and they did not wait 5 minutes before despawning.

There were zombies at the spot where you saw your items vanish? Like, within the area a player would collect items?

He walked right through that spot, a split second after they disappeared.

This Happened to me a few times. As Jug said Me and him got our items back after being nagged at my an Enraged Zombie that killed me with my items at least 5 times... This Is very strange that it happens for you and not for me... Well Sorry for you :/