IRS letter claiming taxes due on 1099-Q

I received a letter from the IRS on my 2023 tax return saying I did not claim my 1099-Q withdrawal (issued to me, but for my son) income and that I owe taxed on it as well as removed the $2500 child tax credit.  I entered my 1099-Q info as well as my 1098-T info and other college expenses supporting the 529 withdrawal as non-taxable.  Turbotax walked me through adjustments to my education expenses to allow the credit if I recall correctly.  I looked at my 1040 and the 1099-Q info gets recorded on schedule 1, line 8z.  However the 1099-Q worksheet does not get filed.  Error check was clean when I filed and I have followed this process for the prior 3 years of his college education.  Any idea why the IRS called this out?  Is there issues or missing documents Turbotax did not send?