Recently, I received a second Notice of Assessment from Revenue Quebec saying I now owe $400 due to a miscalculaiton on my 2019 taxes from 2 years ago. (The original Assessment mentioned no issues) After researchign the problem, it turns out that TurboTax online automatically inputted a 'carry forward' on the Alternative Minimum Tax box. This is something I never inputted or even was asked when filling with the TurboTax Expert. Since my salary is much lower than $200,000 per year this is not something I qualify for and is why I was not prompted with the question upon filling everything out. After learning about the problem, I tried to access my old taxes and only found it using the search function as it did not appear in any other step. The box contained a random sum and it could not even be changed since it was greyed out.

So, not only did I never see this question, the TurboTax Expert also did not see it and I couldn't even change it if I wanted to. This is a clear software glitch and now I am not sure what to do.

Does anyone have any advice?