I just did a quick search and found https://www.ftb.ca.gov/forms/2018/18-3885-instructions.html
There it states under "California law conforms to federal law for the following" and one item listed there is "The additional first-year depreciation, or the election to expense the cost of the property as provided in IRC Section 179, with modification."
Under that is "California law does not conform to federal law for the following" and listed there is "The expanded definition of IRS Section 179 property...." and "the enhanced IRC Section 179 expensing election"
Now on the federal side, in the past, Section 179 could not be used to deduct personal property used in residential rental property. However, the Tax Cuts and Jobs Act eliminated this restriction starting in 2018. This means that landlords can now use Section 179 to deduct the cost of personal property items they purchase for use inside rental units—for example, kitchen appliances, carpets, drapes, or blinds. So I interpret this to be one of the "enhancements" that CA does not conform to. Weather my interpretation is correct or not, I honestly can't say.
