[2.1.17] Furnace crafts recipe with no space for result fluid, which ends up being voided
Posted: Fri Aug 28, 2026 6:24 pm
Attached is a minimal mod which can be used to reproduce this issue. This mod adds an output fluid box to stone furnace, and makes the recipes for iron-plate and copper-plate also produce 10 molten-iron or 10 molten-copper.
When an iron ore is inserted into the furnace, it gets smelted and an iron plate and 10 molten iron appear as products. When you then insert copper ore and clear the iron plate from the output, the copper ore gets smelted and a copper plate appears in the output, but the molten copper just gets voided.
Expected behavior: the different recipe does not start until there is space for it in the output fluidbox.
When an iron ore is inserted into the furnace, it gets smelted and an iron plate and 10 molten iron appear as products. When you then insert copper ore and clear the iron plate from the output, the copper ore gets smelted and a copper plate appears in the output, but the molten copper just gets voided.
Expected behavior: the different recipe does not start until there is space for it in the output fluidbox.