Your child tax credit may be lower this year if your income increased. The credit is reduced when your income reaches a certain level. Please view the Turbo Tax FAQ below for more information.

https://ttlc.intuit.com/questions/3029430-why-is-my-child-tax-credit-smaller-this-year

Because a child tax credit reduces the amount of tax you owe for the year, it may also reduce how much you need to have withheld from your paychecks. This credit can lower your tax by $1,000.00 per child, but only if you have that much tax. Therefore, you should consider increasing the number of allowances taken on your W-4. Please view the Turbo Tax FAQ below for more information.

https://turbotax.intuit.com/tax-tools/tax-tips/Family/Child-Tax-Credit/INF12004.html