@nscott82
My case is similar to yours. My schedule 1 (Form 1040) has 'See Stmt' in description of entry z of Part I Additional Income which is corresponding to entry on line 8z of Section B of Schedule CA (540). But 8z description in Schedule CA (540) is empty. In my case, the other income is from 1099-K of which balance is 0. That's the only difference over 2020 tax return. I'm also guessing that's the cause of the error but I mailed my state tax return without any modification. Let's see CA accepts my tax return and Turbotax refunds my state e-filing fee.
Funny thing is it turns out the 1099-K from eBay is their mistake. eBay should not send me 1099-K because I'm not eligible. I received a mail about that from eBay YESTERDAY.
