Yes, but in that case, the recipe is already selected at the time iron plate is put in the input buffer. It can only be steel plate. I understand from an implementation standpoint how your comment explains the behavior, but it seems like a bug to have iron plate in the input buffer, but consider the...

https://forums.factorio.com/viewtopic.php?f=47&t=33342 So, I think there is still an issue here. As I posted on that other thread, the inserters clearly respect whatever is in the output slot of the furnace (i.e. it won't load copper ore into a furnace with iron plate in the output buffer), but ...

I'll post on the other thread, but I think there's an actual issue here. It's clear that inserters peer into the state of the furnace to decide whether or not to load a resource, but does so inconsistently. It looks at the output buffer/slot, but not the input buffer/slot.

Hello, I attempted to build a high throughput and reasonably efficient smart foundry; I believe it is impossible due to an inconsistent behavior of (dumb) inserters feeding furnaces. Issue : An Inserter will consider the output slot of a furnace when deciding what to load, but will not consider the ...