The custodial parent who the child lived with more than half the year is the parent who can claim EITC. If the other parent was not the custodial parent and claimed the EITC, then that parent made a mistake or purposely claimed benefits the parent should not have claimed.
The custodial parent will have to print, sign and mail their return if the benefits were incorrectly claimed by the other parent. Later in the year, the IRS will contact both parents requesting documentation to determine who could rightfully claim the benefits. The winner gets to keep the benefits they claimed. The loser gets to pay them back and perhaps also penalties and interest.
