My student/child got a notice about a calculation error from 2020 taxes

My child (18 at the time, 19 now) received a letter from TT/Intuit that there was a calculation error on their 2020 Federal filing.  I reran it and it looks (only) like the Tax (Part III, line 15) was miscalculated.  The "tax" on a three digit number should not be a four-digit number.  

 

Has anyone else had this happen?  Looks like we have to help the kid file an amended return (not a big deal) as I'm sure the IRS was happy to have taken a free loan from us for the YEAR (more than they usually "borrow")

 

Looks like I need to start duplicating my TT work with doing my taxes by hand...  whee.

 

Is this really just an issue of an amended return with a phone call to TT/Intuit to verify what I'm doing?