The Case of the Mislabeled eBook

I recently got an ebook on Kindle Unlimited, but when I filtered for Kindle Unlimited books on my device, it didn't show up. It didn't show up in "All" either. However, when I turned off the "Books" filter, it showed up. With some experimenting, I discovered the book was listed as a comic for some reason. Can I change that on the Kindle? I don't see a way to do it.