iPad Mini seems to freeze up

I have an iPad mini and also have a Kindle App on it. It seems that when a book cover shows on the screen the iPad freezes. I have tried to do to Safari and clear the History and Website Data, but I guess it clears but the cover is still on the screen.

I then shut it off, restart it and the cover clears.

1. Does anyone know why this freezes?

2. Is there a better way to handle this.

Than