Originally Posted by sparklemotion
That's interesting and something I hadn't considered before. I do have all my books on my device. Maybe I should move some of the non-kindle books to the cloud and see. It's a weird quirk, but I like to keep all my books on my device just in case I want to access one. I may move them as an experiment though to see. I only have 3 pdf's, but who knows, it could be them as well. Thanks for your reply and suggestion.
The Amazon Kindle eReader on the Fire reads books on the device AND on the Cloud at the same time. Move the suspect files to your PC just for the experiment.