You wont believe what's breaking it...
My cell phone chrome browser. And I can reproduce it....
Update: It's fixable though.
To Break it:
I use my cell phone to edit the rule trigger. Any trigger from any rule. I save it and when I go to edit the actions the rule seems to be broken but its not.
Cell phone is a Samsung S7.
To fix it:
I use my desktop chrome browser and go into the same rule and simply edit and save the trigger the actions are editable again.