Although it is rare that removing income would increase your tax liability, it could happen. All entries interact with each other on the tax return. Without seeing your actual return, it is impossible to tell.
One example is if some or your dividends were from REITs, this would be the most common reason for an increase in taxes. REITs (Real Estate Investment Trusts) often have a Qualified Business Income (QBI) component that is a new tax deduction for 2018. If you remove them, it also reduces the credit.