A federal judge cast doubt on Bayer AG ’s proposal to neatly resolve all future lawsuits over the safety of its Roundup weedkiller, potentially snagging the German company’s attempts to move past the massive liability. Bayer said recently it would pay up to $10.9 billion to settle tens of thousands of current Roundup cases and create a system for handling future cases. The deal came after three juries in recent years awarded large verdicts to plaintiffs alleging Roundup caused non-Hodgkin lymphoma, spooking investors. U.S. District Judge Vince Chhabria in San Francisco, who must approve the class action, said Monday he...