The trust is listed as the beneficiary of the IRA and the distribution of the IRA was made to the trust in 2018.
The trust did not make the distribution to the beneficiaries of the trust until 2019.
Does the trust have to pay taxes on the IRA in 2018 or can the income be passed to the beneficiaries in 2019?
IRC Sec 663(b) allows a trust to elect to treat amounts paid or credited within 65 days of a tax year as credited on the last day of the preceding year but I don’t think it works the other way. Also, look at terms of the trust to determine whether it was required to be distributed.