I am having the same issue. During preparation, TurboTax picked up that the $300 from prior year was an error and cited the new law showing that we could take up to $600 as married individuals. I changed it to $600 and the error went away. When I run the Federal Review I no longer have any errors and it calculated the $600 credit correctly. However, when I run the Final Review after the State Tax section, it takes away the $600 and reduces my refund accordingly. I even input the $600 as an override in the Two-Year Comparison form and the calculation error still occurs when running the Final Review. I agree it's a programming issue and will wait it out a bit more to see if this issue is ultimately corrected by Intuit. Very annoying!
