There is a new cap/limit for state and local taxes for 2018 due to the Tax Cuts and Jobs Act that was passed in December of 2017. In 2017 and before you could deduct state and local taxes on your federal return without any limit on the amount; beginning in 2018 state and local taxes is limited to a $10k deduction.
It sounds like this is the difference for you from 2017 to 2018. The total of your real estate taxes and "state and local taxes" (most likely your withholding from W-2s) is $9,616. If you also entered DMV fees or other personal property taxes that would likely be the remaining $384 to get you to the new $10k limitation.
You can read more about these changes in this comprehensive article:
https://ttlc.intuit.com/replies/6971774
