I have just been contacted by the CRA about the Medical Expense line as well. It turns out that my spouse's return included a Medical Expense claim of ~$15,000. However, we did not enter that information, and, upon revisiting the Interview section the Medical Expense section has not been activated at all.
Unfortunately, I missed that detail when reviewing the summary and now need to figure out what to do as the CRA is now requesting a review. I have filed a support request already, but I am concerned the software has a bug.