Is there a setting hidden somewhere to turn on botionblur in the viewport render?
I get motionblur with an Alembic but the red Torus animated in Maya does not have motionblur in the viewport.
In the VFB both do have motionblur.
Motion blur is not rendered in IPR due to stability reasons. Animated alembics work since the animation data is already baked in.
In this case its a bug that the Alembic is rendered with motionblur.