The IRS lowered the withholding table amounts in 2018 due to the lower income tax brackets from the Tax Cuts and Jobs Act of 2017. To avoid this scenario for 2019, you can adjust your withholding allowances and/or amounts utilizing TurboTax’s W-4 Withholding Calculator.
See this IRS news release from last January 2018 regarding the new withholding tables:
https://www.irs.gov/newsroom/2018-withholding-tables-now-available
