Robots not processing some stacked assignments in robot work queue
We've got a robot working fine when we create new assignments for it, but we've got 3 assignments in a robotic work queue which cannot be released. I've tried to stop and start work queue but these 3 assignments remain in the work queue. What I'd like is to process these 3 stacked assignments, any idea? I attach an screenshot.
Why doesn't the robot process these 3 stacked assignments?