Pencil sketch caused critical exception after green screen

On the color page, I had a node with a qualifier on a green screen, and a power window (garbage matte), and then I added alpha output to create transparency as intended. I then dragged and dropped a pencil sketch node after that first node. I didn't like the result (the green screen transparency was ignored), so I started to tinker with the pencil sketch node connection - connected alpha lines, and adjusted parameters on the pencil sketch settings... and DR popped up a "critical exception" error, shown below, that "parameter group Polygon W with timeline id 0 is not allowed in the markstore." That looks like a bug.

crit exc.jpg (86.87 KiB) Viewed 247 times

I quit DR, re-entered, and decided not to retry the node tree (I was exploring for creative ideas and it wasn't mission critical to fix that day).