Factorio Forums

I found out that you can turn the belt and turn it back to stack items on it. It looks like items from back go through the front ones and then stack into one-packed-thing™. So, it is like unlimited storage for everything!
Sure, you have to waste some time packing it, just like in real life.
Here is the video:

This seems more like a bug to me. Never happened to me though (not that I ever tried).
Edit: confirmed on 0.18.17. Maybe some mod can move this to bug reports?