I recently discovered the drop bed function, and immediately proceded to jam up my camera so that I couldn't get the lens back in the body. I was sure I hadn't bent, forced, or broken anything, but I couldn't get the lens back in. I looked carefully, and the linkages all looked good, and nothing looked broken or bent.
What I discovered was that when extending the bellows, I had pulled the inner rails straight out of their guides. After a little careful seating on both sides, and I was able to get them to slide back in. After that, everything went right back in, and afterwards worked exactly as it should.
Not really intending to necropost here, but some Crown Graphic owner might run into the same situation, in which case, they should check this.