With a full inventory, picking up a loose item on the floor behaves as expected and the item stays there, but opening a chest with nowhere to put the new item destroys it instead of leaving it loose on the ground.
Seems to be a bug originating from or otherwise affected by a change between this version and 1.8.1
[1.9.0 FIXED] opening chests with a full inventory destroys the new item
Re: [1.9.0] opening chests with a full inventory destroys the new item
You are right. I've fixed the issue and improved feedback on when your inventory is full (play different sound and do not play pickup animation).