Bear in mind this survey is always more volatile than the ISM, and there may be an outsized July 4 long weekend effect, too. But these are bad numbers.
July sales always looked unsustainably high relative to the level of mortgage applications so a correction was due. This drop in sales does not mark the start of a sustained weakening.
It is still too early to call the end of the manufacturing slump because the stability of July output might be little more than a seasonal effect, ... this report probably means the worst is over.