Hello, I've been experiencing this problem while training and while hunting for drops. I decided to post this up after spending hours trying to hunt for 60% Helmet for Dex scrolls at memory monk and something like this happens (see SS). As you can see, a 60% scroll dropped and both my pet and I were unable to pick it up. Can this possibly be fixed? I really do not think that trying to avoid killing monsters near the edge of a map is a good solution to this...
There are fixes being made for this in the new source. It's also possible that it was a visual glitch and if you change channel and back it might disappear, I had items get stuck and the pet looted it but it stayed on the screen.