Arnold renders same frame for entire sequence of images - point cloud

[foutjm]

so i am rendering a point cloud animation with Arnold in max 2019 (Arnold version 2.0.938) .(same problem in 2018)

i am using a display volume to cut the cloud and animating the display volume to reveal portions of the cloud over a few frames.

if i render out each frame separately everything is fine, all renders correctly.

but if i render out a sequence of images or even a video it just takes the first frame and renders it multiple times. the display volume doesn't appear to be moving at all.

this problem seems like it may have come with a recent upgrade to windows 10 across the board at work.

also having the same issue on home machine.

any help is greatly appreciated.