Judges on the U.S. Court of Appeals for the Seventh Circuit on Tuesday appeared wary of Aearo Technologies’ bid to halt litigation against its parent company 3M over allegedly defective military earplugs as the subsidiary goes through Chapter 11 reorganization.

Judge Frank Easterbrook poked at Aearo’s argument that a lower court judge failed to consider exceptions to a Bankruptcy Code rule limiting automatic stays to claims against debtors.