Those who want make a big deal out of the fact that this number was down are cautioned to cool their jets (a technical term). When you look at the details of what happened here what you see is a bunch (another technical term) of small changes that net out to -3,000. Which means that nothing happened. The level of manufacturing employment is up 159,000 so far this year. That is the number that matters.
And, as the chart reminds us, we see the occasional month in which total manufacturing employment falls. Last year it was July. This year it was August.