Yes, I've learned how the law works. These are all bond funds. One is nearly all California tax-exempt and the other two contain less than 50% California state bonds (the remainder is other states), so an adjustment needs to be made in the state return.
The adjustment at the state level is difficult to make because Turbotax isn't starting out with a number that makes sense. I can separately calculate what it should be and put a number into the form to make it come out right, but it seems like TurboTax isn't doing the right thing.
(This is less about tax law and more about how TurboTax works.)