Thought they may have screwed up the diag or I was going nuts...
The other possible 'gotcha' is that there are 2 styles of PWM control and of course they are also the reverse of each other: 1 uses zero or very low pulse duty-cycle = full speed and as duty-cycle increases the fan slows down. This is safest because if the command wire is cut or shorts the fan runs a full speed. The other control method is 100% duty-cycle = 100% speed. Anyone ever check to see which Bitmain uses?
Bitmain uses no-wire = 100% speed. I removed bloue PWM pin from fan during Antminer S5 overheat times. It forced the fan to run at 100% speed regardless of firmware fan control bug.