Do you have any sense for whether the confusion was related to ranked choice itself, or a poorly laid out ballot?
When rolling out ranked choice, I would expect to need lots of additional messaging before and during polling so nobody is surprised. And also a complete re-evaluation of the ballot's layout to ensure it's usable. I have no idea if either of those happened in CA.
Edit - looking at TimJRobinson's post below, if that's how CA cities laid out their ballots, I'm not surprised there were many errors. That sea of bubbles is hard to read and very easy to apply a pen mark in the wrong place. At minimum, the bubbles themselves should be filled with the number which they represent.
When rolling out ranked choice, I would expect to need lots of additional messaging before and during polling so nobody is surprised. And also a complete re-evaluation of the ballot's layout to ensure it's usable. I have no idea if either of those happened in CA.
Edit - looking at TimJRobinson's post below, if that's how CA cities laid out their ballots, I'm not surprised there were many errors. That sea of bubbles is hard to read and very easy to apply a pen mark in the wrong place. At minimum, the bubbles themselves should be filled with the number which they represent.