Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I suspect that your shredder is, quite simply, 'broken'. No such bar should be in the path of the shredded material. It might be one of several things... but basically your shredder needs at very least some disassembly and fixing.
My guess - though it's only a guess without seeing it - would be that the paper sensor switch has gotten stuck in the paper path, after a jam-up was pulled out upward. This could well be the problem.
(If you took a photo and posted it, perhaps I could tell for certain.)