TurboTax is aware of this e-file issue and is working towards a solution. An update is currently planned for April 12th, 2019 to resolve this e-filing
issue.
You may still see a warning about the
excess contribution, but you should be able to e-file. You can check out
this TurboTax FAQ for more
information: Excess 401(k) Contribution Preventing E-filing.
If you haven't included the excess deferral in wages, please follow the steps in this link: How
to Report Excess 401(K) Deferral in TurboTax Online.
