When amending 2017 you should have corrected the carryover information in your 2017 tax file by manually carrying over the changes from your 2016 amended tax file. If you amended 2017 before starting your 2018 tax return you should have then transferred in from the amended 2017 tax file, otherwise you would need to manually carry the changes from the 2017 tax file into your 2018 tax file (amending 2018 if you did not do that before filing your 2018 tax return). The result will be a correct 2018 tax file to transfer into 2019 TurboTax to begin your 2019 tax return.
If the amendments were otherwise correct without manually carrying over the changes from year to year, you can just make the correction to the incorrect values in 2019 TurboTax after transferring in from your 2018 tax file, or, preferably, you can make the corrections in your 2018 tax file so that it will have the correct information to transfer into 2019 TurboTax. (I'm not sure I would attempt this with online TurboTax, if that's what you are considering. You'll want direct access to the worksheets.)
