I have experienced this bug, however after a few seconds, the item eventually appears either on the ground nearby, or at the location where it originally spawned.

I would consider this a feature, not a bug! I would love to be able to have a character for the different groups of friends I play with.

This happened to me after the 2013-12-18 update. A zombie knocked me unconscious and when my screen stopped being black, my unconscious character slid along the ground, colliding with buildings, until I logged out and back in.

At that point, I was not unconscious, just bleeding.