V8 - Nudging curves/hatches w/history makes display go funny

In the attached file the hatches are history associated with the curves. The yellow hatches are boundary hatches. I select the curves and then using the arrow keys, nudge them first up 1mm, then right 1mm. Aside from the long calc time to re-figure the boundary hatches, notice the screen goes black each time it updates.

What I can’t reproduce on video is that although the curves remain selected after the first nudge, something has lost focus - so the second nudge from the keyboard doesn’t work until I do something like right click in the viewport and pan the view a bit. The screen capture software I’m using seems to do something to the display so that this problem doesn’t happen while it’s running.

Note also that one hatch gets lost after the second nudge, don’t know why either.
NudgeDisptest.3dm (2.2 MB)