TL;DR
When using smart belt dragging, undergrounds are automatically placed when an obstacle is detected. However, if there are no undergrounds in inventory, a straight belt is placed. When there are objects on the belt, this will cause side-loading. Ghost underground belts should be placed instead.What ?
This is what happens:This what I think should happen:
Why ?
Prevent a mess of mixed items on belts if straight belts are placed and cause side-loading.This is not a bug as such, as I think the code is probably working as designed, however, I think the design leads to an inconsistent and unexpected player experience.