Bug when creating conditionals

I am experiencing this exact problem as well. In my case, I have the choice of 4 options with 4 corresponding field sets to show.

I have done this with much, much more complex choices in the past and have not had a problem however now I get the illegal choice error and my additions are not allowed. This appears to be happening when I add a few conditionals and then decide to add a new one to the mix. When I add the new one, it will trigger the illegal choice problem.

I have discovered a workaround. It is a bit tedious but it requires you to delete your existing conditionals and add them all at once before saving the conditionals. I've done this several times to make certain this is the case and if I do delete the existing conditional rules I can add all 4. If I need to add a 5th, I then need to delete the existing 4 and add them all at once again.

It is tedious but it works.

This is the case with the existing DEV released 28 Jul 2023 and the 7.x-4.26 Stable release, released 28 September 2023.

Cheers,
Andrew

You can probably use git bisect to figure out which commit broke it. That would be very helpful for fixing it.