I was on normal difficulty testing the Warden vs a bunch of zombies, then I killed Warden and some zombies to not cause too much lag. A zombie walks up to 2 items(for example an iron sword and rotten flesh), looks down and stands completely still. Then it starts picking up the sword, then instantly the rotten flesh continuously and never stops doing it. And the zombie never moves. I only had tine to test it on zombie once I found that weird moment today. 

Here is a link to the video I took of the bug, cant find a way to put the visual on this page from my phone: https://youtu.be/2RwpPjWB6ZU