Two months after Bayer agreed to resolve thousands of lawsuits brought over Monsanto’s Roundup for as much as $10.9 billion, lawyers told a federal judge in California Thursday that most of the agreements are now uncertain.

U.S. District Judge Vince Chhabria of the Northern District of California, who oversees the Roundup multidistrict litigation, scheduled the hearing, held via Zoom, after receiving numerous confidential letters from plaintiffs attorneys insisting that Bayer had reneged on their agreements.