Factorio Forums

An item can get stuck inside the right half of a a splitter with priority output set to the left side when the left output is blocked.
It happens like half of the time and the item may randomly continue flowing after a random time in the order of magnitude of many (10+) seconds.

I'd expect this item to continue on the right side of the belt since there's clearly space for it there.

How to reproduce (see image for details):
Place straight belt with 1 splitter in the line and enough space after the splitter to it won't back up.
Set the splitter output priority to the side where there's no belt coming out of it.
Place stack inserter (probably irrelevant but stacks make the problem more visible) and a chest.
Put a stack of 100 concrete (or I guess any item) in the chest.
Observe an item stack getting stuck like half the time you try this.

Technically there are no game play bugs here, just some visual artifacts.

Splitter graphics were made before item stacking on belts was a thing, and splitter was supposed to hide this area of lines. Stacking items is slightly going past the area covered by splitter structure and so you see those items, which is the only thing that may need to be adjusted.

As for the items, they are intentionally held on the input side until another item arrives to replace that item. As far as i understand, this logic is mandatory for priority splitters because if the items on the priority output and on the input would not be perfectly in sync and there were no items buffered on the input side, there would be a possibility of gaps being created on the belt and there were lots of bug reports of people complaining about priority output not being compressed, so this buffer logic is unlikely to be ever changed to make that item "unstuck".

I don't see the graphics for the splitter ever changing at this point and item on belt rendering is already iffy at best when it comes to performance and layers.

With that in mind, I'm moving this to minor issues.