Maybe because she went in there once, and now she thinks it's ok. Dogs have a phenomenal sense of smell. If she smells urine, she may think that is where she should go. I would throughly clean the crate with something made to remove pet stains. Then if she continues to go in the crate, either give up and put a pad in, or move her to a small crate for training. Hope this helps.
I left my yorkie in a play pen with a pad while I was out until he was pad trained enough to leave out all day. Then when I came home, i kept him leashed to me so I could make sure he didn't have accidents without me noticing. I was able to give gentle correction on the spot.
The first year he basically was either in the playpen or tied to my hip. Good luck!