We tried to see Judy two weeks ago when we were there. On Wed, the app had 4 or 5 times listed for her. We got there a bit early and stood in line to wait, but it ended up being just Nick. And the cast member said Judy wouldn't be out at all.
We tried again on Friday, and while the app listed several times when I looked at it before opening, by mid morning all of the times were gone except for one that we couldn't make in the late afternoon.
Hope you have better luck than we!