Turbotax 2024 Home and Business flags any contribution more than $19500 as an excess contribution, and reduces the deduction. I have updated my software daily but this continues to be an issue. The problem is Part V of the Keogh, SEP and SIMPLE Worksheet. This section limits the contribution to the sum of $19500 and the matching amount from the employer you entered under Part I, Section 5. This erroneous limit then overrides section IV's contribution limit of $21450 and the amount you entered in part I, Section 5 then overrides it everywhere that amount is needed in the return including the 1040 worksheet and Schedule 1. When you right click on the form and bring up the "About" information, the form is still showing the $19500 limits throughout. It appears that this form was only partially corrected and this makes it continue to malfunction.
This experience has been confirmed, and a solution is being implemented. Some TurboTax customers who have contributed to traditional SIMPLE IRAs may have an issue when entering their contributions into their returns. They may get an error saying that they have contributed too much and need to withdraw the excess. See this TurboTax FAQ to sign up to receive notifications regarding this update.