Thank you all that replied to my question. The mystery is solved, and IRS agreed to my original filing.
I called IRS today, after waiting for an hour, an agent answered. After telling her that IRS doesn't agree to line 16. She said the problem is with Form 8962, Premium Tax Credit. I had Covered California health insurance in 2021. There are many columns in the form. At first she said, column a and e don't match. Then I told her that my return included Form 8962, therefore my numbers and IRS numbers should match in those columns. After a while, she said that line 5 which should be line 3 (AGI) divided by line 4 (poverty line) multiply by 100 should be much higher. Except that I have received unemployment in 2021, therefore line 5 should be 133%. Turbo Tax is correct again. The agent is very professional and patient. I am happy with the outcome.
I don't understand how disagreement on Form 8962 could led IRS to agree on Form 1040 line 11 (AGI), and line 15 but not line 24. Disagreement on Form should only affect Tax Credit, either IRS pays you because you received too little health premium in 2021 or IRS asks you pay back premium which you had received too much of it.
By looking at the IRS notice, you could never guess it's Form 8962. Lesson learned, should always find out why by calling IRS. Don't just give up and pay.
Once again, thank you all for helping.
