C-philips, I would go along with the anxiety idea. I joined the forum ten years ago, and I experienced very serious behaviour disorder, as did Karma and Archie Bean at the same time. My pup showed a problem from day one, no help from the breeder. He didn't guard specialtoys. Anything, just what he fancied at the moment, And if it's on the floor, it's mine. Removing things by order was impossible , I had to go out of the room and call him, he'd come happily , and then the item was rescued, or he didn't want it any more. Then there was personal space issues and the car saga.
Lots of dogs have problems from lack of training. Others have a mental problem, and most people don't experience it. It's terrifying, and if your dog has drawn blood, that's where you are. We changed our coping mechanism, and I kept him safe from stress. Now I have two dogs easy with people, I realise now the years of tension we had, nearing divorce. In retrospect, I have accepted that like some people, he needed a non sedating prescription drug to reduce his anxiety. There could have been a serotonin or dopamine type problem. His impulse control and stress levels needed help.
I don't want to frighten you , but as other people less aware of his problem at the moment are involved, consider this option. Also , leave them to relax undisturbed, and perhaps try not using the crate, but sleep time behind a baby gate.
I know how upset you must be, But remember that most Cockers are extremely sensitive and intelligent, and get confused , stressed etc. As you say , you have an adorable dog 99% of the time. And a vet check could be useful, with a blood panel test in case he's got a problem. They cant tell you.