Nope, it's Krastorio, but a little less obvious than I thought.
Disabling only Krastorio2, mining the chopper, and re-placing it fixes the issue. Disabling all mods but base and adamo-chopper, mining and re-placing the chopper, saving, enabling Krastorio2 and re-loading: at first it appears okay, but after stopping the engine extra fuel warnings show; mining and re-placing the chopper shows even more fuel warnings.