This is what Spidell sent me when I asked them about it last month
Here is an excerpt from our Federal and California Tax Update Webinars, where we discussed this issue. "The taxpayer includes the income from the IRA distribution over a three-year period unless the taxpayer elects to include all the income in the year of the distribution. California conforms. (IRC §§402(c), 403(a)(4), 403(b)(8), 408(d)(3), 457(e)(16); R&TC §17507) A taxpayer can make a different election for California purposes and, for example, report all the income in 2020 for California purposes but spread the income over three years for federal purposes or vice versa. (R&TC §17024.5)"