Error: Cannot invoke method tokenize() on null object

I've done my best in that regard. I don't know what steps you took to get where the rule ended up. If someone were to report repeatable steps, that could lead somewhere. Where that error is being thrown from does not shed any light on what caused it in the first place. At the point where a Broken Action first shows up in a rule, it can be deleted or fixed. That in and of itself is attempting to prevent a subsequent failure of the rule.

If you want to send me a backup of your database, I could try to learn more about the cause. See PM.

No worries. I'll just recreate it. Thanks Bruce for considering.

I have run into this issue as well (Very frustrating). I have been able to repeat this by clicking back in the browser after clicking on new conditions or rules but not actually finishing the creation of the condition or rule. This seems to mostly happen via safari browser on iPhone.

Don't click on back in the browser. Finish what you started, you can always delete it. For various reasons not worth exploring, back is not a reliable navigation method for our application user interface.

:man_facepalming: I just noticed your comment "And, I found a problem with selecting Custom Action but not completing it." So this is actually a bug you have fixed for the next release. I suppose the back button is just the same as not completing.

Will your fix in the next release "Cure" rules that were already broken by this error? (:crossed_fingers:)

There is no “fix” for the back button coming. If you broke a rule using back, throw it away and start over. Don’t use the back function of your browser when creating a rule.