Mysterious 'undefined' task showed up on Completed Screen

[abegel]

I have a family named AndrewFam with Parent P, and two children A and B. I created a task and deleted it. Then I created a second task and had child A accept and complete it. When I switched Parent P's browser to the Completed tab, I see two tasks on there, not one. The one that was completed is there, but also an additional 'undefined' task. See the screenshot below.

[abegel]

This undefined task has undefined points and an undefined note.

[abegel]

Only Parent P shows the additional undefined task. Child A correctly shows the single task he completed. Child B shows no completed tasks.