Solved
Lyndsy-DenkAccepted solution
Level 3
May 28, 2021 9:19 PM UTC
Now we're onto something. When I promoted the child tasks and recalculated, the Percent Complete calculated appropriately. I created a new parent and recalculated--no fix. Then I created new children tasks, deleted the originals, recalculated--and it worked! I don't know why, though. The task settings all looked normal. But it worked and that's all that matters.
I'm going to have the user who reported this keep an eye out for the weirdness. I suspect it stems from the project template.
Thank you for picking at the details with me.