The plea deal in Hunter Biden’s criminal case unraveled during a court hearing Wednesday after a federal judge raised concerns about the terms of the agreement that has infuriated Republicans who believe the president’s son is getting preferential treatment.

Hunter Biden was charged last month with two misdemeanor crimes of failure to pay more than $100,000 in taxes from over $1.5 million in income in both 2017 and 2018 and had been expected to plead guilty Wednesday after he made an agreement with prosecutors, who were planning to recommend two years of probation. Prosecutors said Wednesday Hunter Biden remains under active investigation, but would not reveal details.

U.S. District Court Judge Maryellen Noreika, who was appointed by President Donald Trump, raised multiple concerns about the specifics of the deal and her role in the proceedings. The plan also included an agreement on a separate gun charge — Biden has been accused of possessing a firearm in 2018 as a drug user. As long as he adhered to the terms of his agreement, the gun case was to be wiped from his record. Otherwise, the felony charge carries 10 years in prison.

The overlapping agreements created confusion for the judge, who said the lawyers needed to untangle technical issues — including over her role in enforcing the gun agreement — before moving forward.

“It seems to me like you are saying ‘just rubber stamp the agreement, Your Honor.’ … This seems to me to be form over substance,” she said. She asked defense lawyers and prosecutors to explain why she should accept the deal. In the meantime, Hunter Biden pleaded not guilty to the tax charges.

The collapsed proceedings were a surprising development in the yearslong investigation, and a resolution that had been carefully negotiated over several weeks and included a lengthy back-and-forth between Justice Department prosecutors and Biden’s attorneys.