Orbital auto miner consumes too much fuel

The logs state that all is fine.

First: You fueled them in 3 stages. That means the first (in your case Iron) gets 3 and the rest 9 will be put into the others. So the last 2 don’t get any. (This will be changed this week as mentioned couple times in forum)

If they took fuel 2 days before then of course they will take them one day later again.