isaacsim.ros2.control prunes the synthesized URDF and drops the fixed joint between an arm and its gripper mount, leaving two root links that urdfdom rejects on ROS 2 Jazzy, so controller_manager never comes up.
From the Grok pain-radar digests, Oct 27-28 2026 (Oct 27 8:41 AM ET through Oct 28 7:41 AM ET digests plus the Haitch editions). Verified live 2026-10-28: issue/PR/thread read; title and state confirmed.