EDIT: from mod feedback & also i just found it in the codex guide, this is a feature not a bug. @wicked rapids
~~disclaimer: I'm honestly unsure if this is a feat or bug, but I'm leaning toward bug 'cause the little indicator bar on the trade station input is green, which implies to me that the input is ok.
expected behavior: any trade station can receive its expected shape regardless of the level on which it's being delivered.
actual behavior: belts delivering correct shapes on the 2nd level result in the trade station locking down and its overall indicator going red. only moving the input to the 1st level makes the trade station process shapes.~~