Unlike handguns, long guns in CA don't have an approved roster/list. There compliance is determined by features of the long gun to determine if it is eligible.
This AR you asked about IS CA compliant. If you are attempting to purchase this rifle, and buds website is not allowing the sale, then this is a glitch on buds part, as this rifle has NO banned features and even has the CA designation in the model number.
Call buds during buissnes hours at 859-368-0371, 9am-9pm eastern Mon-Fri
Or use the Blue Chat now button at the bottom right corner 9am to 9pm Mon - Sat and closed Sunday.
They should be able to assist you.

Christopher, this is likely a glitch in Buds website Sir. Buds Customer Service can assist you with the purchase at 859-368-0371, 9am-9pm eastern Mon-Fri Or use the Blue Chat now button at the bottom right corner 9am to 9pm Mon - Sat and closed Sunday. Cheers and stay safe!