Turbo Tax showed a different 2018 return when I logged in to get info for my 2019 return

I used Turbo Tax for my 2018 return (and many, many years prior).  I did all of the reviews for accuracy and submitted it online.  I printed my state forms (2 states - work in one, live in another).  I owed over $3K in Federal, which is very unusual for us.  Doing my 2019, I tried to do the import and it would not import the tax file, so I had to log in to 2018 and save a PDF of my taxes.  Upon closer inspection, the numbers don't match.  I went online to the IRS and got a copy of my tax report.  Turbo Tax 2018 (which forced an update, in order for me to open it) showed I only owed around $1K and not $3K+ which I paid last year.  The forced update, to open 2018, changed the return end result.

Why did this happen?  Should I file an amended return to get my $2K overpayment back?  Should an accountant review this?  Is the updated 2018 incorrect?  I'm very frustrated.  My return this year was rejected because the imported AGI didn't match the AGI on my return last year (because Turbo Tax updated and changed my return.)  I realized I never printed a pdf of my returns last year, so I'm at a loss.

I thought Turbo Tax guaranteed accuracy and the best refund.  Not sure how this should be handled.