What geometry do you want to motion blur? I did a quick test, and I see the emitter and the hair are both blurred.
Hi thre,
According to solid angle web to set up the hair and fur (https://support.solidangle.com/display/A5AF3DSUG/Hair+in+MAXtoA) you need to change the rendering method to "mr prim", so "This will allow hair to render as native Arnold Curves", but If you do this you got no motion blur:
(mr prim rendering method = no motoin blur)
If you the leave the rendering method in "geometry" or "buffer" it seems to work, but of course is not using arnold curves for the rendering decreasing the performance
buffer rendering method
PD: And only "mr prim" method works with 3dsmax IPR (active shade)
I get motion blurred curves with the latest maxtoa:
works fine here as well, no need to mess with render panel settings, just make a camera, enable motionblur and raise the value from 0,5 to something higher to provoke the motionblur incase you have very little motion.