2.4 Error trying to edit button app: cannot invoke method tokenize() or null object

I just switched to 2.4 and want to edit what happens when I push one of the buttons on one of my Fibaro 6 button key fobs. I went to the device and then the "being used by" section and I got here:

I clicked on it to edit it but when I do I get this error:

And the log said this:

What caused this and how do I fix it so I can edit what that button does?

It seems to be working for me with creating a new rule, but I haven't been using the button app previously for anything to know if anything changed with 2.4

Have you tried just deleting the rule and recreating it, instead of trying to edit it?

For whatever reason, when I tried to go back into it just now it worked perfectly fine. Maybe for some reason it took a while for everything to rebuild/repopulate with the new UI?

Who knows? But as mysteriously as it stopped working, it is working now.

In the immortal words of Annie Hall: "La de da, la de da".