Excess of assets 401k

[goncalvesjj77]

I had an excess contribution into my 401k of around ~$1,000 in 2018 as a result of changing employers and miscalculating the deposits from each. After voluntarily reporting the issue to the 401k plan administrator, they indicated that I'd receive the excess pre-tax money back, and that a 1099-R would be issued this year (2019) which will be used for tax filing purposes in Q1 of 2020.

I'm not sure I quite understand the tax reconciliation process if the excess contribution is made in 2018 and no changes are done in the W-2's (I was told no corrected W-2's would be issued), the excess money returned in 2019, and the taxes filed in 2020. I'm concerned I'll get doubled taxed or pay interests I should not have. Can anyone share their experience and how they found resolution?

[PaulaM]

You can report the excess deferral in 2018 in the Less Common Income/Miscellaneous Income section without 2019 1099-R. Enter '2018 excess 401k' deferral as a description. With the excess already reported in 2018, you can disregard 2019 1099-R but keep for your records.