Carrying around a second rifle, playing with actions and inventory. As I was walking out of town with this fresh rifle I bumped into a chunk of decoration on the ground. The rifle then disappeared.

The first time this happened I tried firing the invisible rifle to see if it was still there, even though hands showed empty and the rifle appeared about 20 seconds later.

Started recording and tried to reproduce:
https://www.youtube.com/watch?v=TxA27hU6n3g

The second time the weapon was gone for good, poof. Stuck around a few minutes and combed the ground to see if the server would eventually pop it back up but there was nothing.