Smart/ Programmable splitters seem to have output priorities in certain combinations, to the point where after a single item in the 'non-prioritized' port, that side entirely stops working.
This issue only seems to occur if the input belt is Mk1, 2 or 3.
- If left and right outputs are in use, right side is preferred
- If left and center outputs are in use, left side is preferred
- If right and center outputs are in use, center is preferred.
How to fix:
- Connected the third output and keep items flowing through it.
If items stop moving through that output, the original issue comes back.
- Set the empty output slot to the same item as the output with a designated item, setting any other item will not work.
After setting the unused output to the designated item from the other output, you can set it back to 'none' and it will keep working.
Videos showcasing the issue:
Video showcasing extra info and the workaround: