Factorio Forums

1. Copy two or more already active entities with input or output pipes (or both) containing fluids.
2. Paste to a location making sure none of the new pipes will be connected.
3. Trying to change the recipe in one entity will result in a "Can't mix fluids" message and set the recipe to nil.

If n-1 pasted entities' recipe are set to nil, changing the nth entity's recipe will be successful and then you can go back and change the other ones. This behaviour does not occur if no pipes are involved in the copy-paste.

Thanks for the report however that's working as intended: you can't set a recipe that would cause fluid mixing and by copying the other recipes you configure the assembling machines to reserve the pipes they're connected to and prevents other assembling machines from switching to recipes which would conflict.

If this is not a bug then why does recipe-switching work when only one entity (with pipes) is pasted or if n-1 pasted entities' recipe are set to nil as described in my report?