Factorio Forums

The description in productivity module says "creates aditional stuff with no raw resource cost", but there is one inconsistency that electric mines with producticity modules still subtract aditional resources from the resource field. That makes productivity module have practically the same effect as speed module. (I don't know why i am writing it here, when i wish that instead of fixing this you'd rather create more awesome features )

I believe that the code to "eat" resources as you say just runs each time an item is produced, no matter if it's made from regular mining or productivity boost.

Yes, the productivity just fires the same code as normal mining, this is a bug that will be fixed. Thank you for the report.