Factorio Forums

I was messing around with making a compact In/Out (IO) output 4 belt balancer with a 90 degree turn say for even train unloading situation when I found this blueprint underground belt bug. It seems to me like the single unpaired underground belt is affecting the direction of the paired underground belts somehow, the blueprint itself displays the correct belt direction but when built all logic is thrown out of the window and the single unpaired underground belt takes priority over finding its pair and skipping over the underground belt in the middle to find it, reversing the direction of the pair and still ending up single. Its a tragedy.

(1) On the left is the original belt setup,
in the middle it shows which direction the belts are facing in the blueprint
and (2) on the right is after the blueprint has been built in vanilla version [0.17.7].
Here there is no problem with all underground belts being paired.
Below is my example of what happens when you blueprint the original and rebuild it. Original on the left, copy on the right, the underground belts are facing the other way in the copy. I cannot fix the blueprint either because I'm trying to make it compact and there is no space to pair the single underground belt with another one so this logical bug happens.
And here is the image of the blueprint showing all the belt directions and the built copy version which has the underground belt facing the wrong way. I extended it also by 1 tile from the original to test the single/pair theory.
You can find the blueprint here:
Copy blueprint

It is a very rare use case but never the less the logic is slightly broken and misleading from the blueprint tooltip direction to the built version. Things just don't add up, you're told one thing but it ends up being the opposite.

It seems to be dependent on the order you revive the ghosts in.
Fixed in Version: 0.17.9.

Changed how reviving underground belt ghosts works, let me know of you discover anything strange.
Thanks.