We received a letter from the IRS stating that I had a substantial tax understatement penalty on our 2018 taxes in the amount of $1,714. 1040, Line 10, 11, and 13?

Changes to our 2018 tax return
Income and deductions
Retirement income taxable
     Shown on Return $0
     As corrected by IRS $37980
      Difference  $37980
 Interest
      Shown on Return $0
     As corrected by IRS $101
      Difference $101
Retirement income gross
Shown on Return $0
     As corrected by IRS  $597
      Difference  $597