Also, if this is a married filing joint return, and one or more of the W-2s belong to the spouse, make sure you have the "Spouse W-2" box checked on the input.

If all of the deferrals did belong to just the taxpayer, then as George said your client will need to remedy. Otherwise, the deferrals in excess of $19,500 may need to be added back as income in the "Excess salary deferrals" field.

- Rebecca