Item Duplication

I've seen this since about 1.7. Setup up a hopper clock... two hoppers facing each other. Put in one item.

Then play the server world for a bit. After a few days that single item becomes 20 or so... Seems to happen most often if the area is stitched with hoppers to create loaded chunks... or a really long hopper line.

I think what's happening is when the world shuts down (due to no players), or the chunk is unloaded and the item is in transit, it places the item in both places. Thus the duplication.

It's been happening contently since 1.7 so I know the problem is there. But it's hard to replicate since the conditions are so specific. (granted I've got an iron farm in my world and my 10 item hopper clock this morning had 21 items in it.)