It depends. It sounds like you may have imported your Quick Books into your Turbo Tax return. At this point, you may need to review your self-employment expenses and edit your vehicle information. If there are two cars listed as business vehicles in the vehicle summary page, you will need to delete the vehicle that doesn't belong by selecting the trash can icon to the right of it.
Thank you for replying, but as I think I stated in my original question: I only own and use 1 single vehicle. That's what makes the duplicate "undefined" listing such a puzzler. The system seems to think I still have a second vehicle; I did own an earlier MKZ Hybrid, but that one was totaled and taken out of service during 2019. It no longer appears in my QBSE.
Even though you took the MKZ Hybrid out of service in 2019, it seems that QBSE or TurboTax still retained it as an undefined vehicle. Is there an entry with a wastebasket that you can just delete?