[2.1.20] Possible inputs lists same item multiple times when recipes differ only by fluid temperature

[Bananycus]

What did you do?

I made a mod that adds two furnaces and their recipes.

The Different temperature furnace has three recipes. Each one takes 1 iron ore and 10 water. The water temperature limits are maximum temperature 40, temperature 40 to 80, and minimum temperature 80.

The Multiple fluid furnace has three recipes. Each one takes 1 iron ore and 10 of one fluid: water, sulfuric acid, or lubricant. Those recipes set no temperature limits.

I crafted both furnaces, placed them, and hovered the item ingredient slot on each one after opening the entity GUI.

What happened?

On the Different temperature furnace, possible inputs lists iron ore three times, once for each recipe. Its three recipes each take 1 iron ore and 10 water. The water limits are maximum temperature 40, temperature 40 to 80, and minimum temperature 80.

different temperature furnace

09-23-2026, 02-37-14.png (251.93 KiB) Viewed 308 times

On the Multiple fluid furnace, possible inputs lists each fluid once, with iron ore under that fluid: water, then lubricant, then sulfuric acid. Those recipes also take 1 iron ore and 10 of the fluid, and they set no temperature limits. That list looks correct.

different fluid furnace

09-23-2026, 02-44-03.png (375.24 KiB) Viewed 308 times

What did you expect to happen instead?

The Different temperature furnace should list iron ore once, together with water, or list water multiple times, once for each temperature with iron ore listed under each water. Every recipe on that machine accepts the same item and the same fluid. Separate possible input groups look correct when the fluid itself differs, which is what the Multiple fluid furnace already shows.

Does it happen always, once, or sometimes?

It happens every time the item ingredient slot tooltip is opened. It does not depend on a particular save. Any furnace with several recipes that share an item and the same fluid, and differ only by minimum_temperature or maximum_temperature on that fluid, lists that item once per recipe. I did not test if the bug appears if the recipes dont use fluids but share the item. The attached mod is only an example of that case.

[boskid]

Thanks for the report. For 2.1.21 i made this tooltip to only show one of each item.