President Trump’s financial disclosure, released on Wednesday, included for the first time repayment of more than $100,000 to his personal lawyer, Michael D. Cohen, in 2017, raising questions about whether Mr. Trump’s sworn filing from a year ago improperly omitted the debt.

In a highly unusual letter, the Office of Government Ethics alerted the Justice Department on Wednesday to the omission, telling Rod J. Rosenstein, the deputy attorney general, that the ethics office had determined “the payment made by Mr. Cohen is required to be reported as a liability.”

Mr. Trump’s financial disclosure, released by the Office of Government Ethics, did not specify the purpose of the payment. However, Mr. Cohen has paid $130,000 to a pornographic film actress, Stephanie Clifford, who has said she had an affair with Mr. Trump. Mr. Cohen has said he made the payment shortly before the 2016 election as hush money for Ms. Clifford, who goes by the stage name Stormy Daniels.

Mr. Trump repaid Mr. Cohen $100,001 to $250,000 in 2017, according to a footnote in the filing.

David J. Apol, the acting director of the Office of Government Ethics, sent Mr. Rosenstein a copy of Mr. Trump’s current and previous financial form, noting in his letter that “you may find the disclosure relevant to any inquiry you may be pursuing regarding the president’s prior report that was signed on June 14, 2017.”