Factorio Forums

In my krastorio 2 + space age save, i've noticed a slightly confusing visual bug that causes assembling machines to have 2 fluid inputs instead of 1.
After some further investigation, it appears that a mod (Secretas & Frozeta) adds a compatibility recipe with the Cubium planet mod, which requires 2 fluids and produces the planet's science pack. (pictured below)

However, the assembling machine, when set to processing units, shows 2 fluid input icons in alt mode. the one with the pipe sticking out of the assembler works as normal, however the one without the pipe doesn't, which leads to some minor issues (i have already rotated my buildings incorrectly once before because of this)
a picture of a small blue circuit line in alt mode below:

This also appears with the "easy electronic components" recipe, which takes water as its only fluid input. I have not noticed this with every fluid recipe in an assembler however, only these two.

I am not seeing any bugs here, some mods added second fluid and possibly the same mods added second fluid box to assemblers to make those recipes craftable. Given this is modded and there was no save file provided i am going to throw this to Not a bug.

Even in base game there are some machines that have multiple input fluid boxes (for example a chemical plant) where for some recipes they will each take a different fluid (like light oil cracking taking light oil and water) but with other recipes they will both merge to take a single fluid (like lubricant recipe taking heavy oil on both inputs). If mods want different behavior then they have to configure recipe ingredients on remaining recipes to use only a specific fluid box instead of falling back into usage of all input fluid boxes.