You are correct, you should not change your W2 because the IRS needs to match it up with your original.
TurboTax is aware of the e-filing issue that you are having and is currently working on a solution. An update to fix the issue is expected to be released around 4/5/2019.
Be sure to sign up for updates to be alerted as soon as there is a solution. If you do not want to wait for an update, you have the option to paper file your tax returns as this is only an e-filing issue.
You can check out this TurboTax FAQ for more information: Excess 401(k) Contribution Preventing E-filing.
