I tried opening more of my epubs in Moon+ and eventually I did find 2 (out of 100) which experienced the same problem you described, i.e. text from page 2 displayed on the same page as the rather small cover. When looking closer I see that these 2 books contain much smaller cover images than I normally try to find. So I wonder if this is what determines how the covers display?
FWIW, I did find that a long press on the small page 1 cover expanded the image significantly - some sort of View All Book Images feature - but you probably know this already if Moon+ is your go-to reading app.
My 407x648 cover expanded to fill the screen, but the 310x500 cover expanded to a bigger image but with approx 1cm black border on all 4 sides. No sign of any text, though.
Last edited by jackie_w; 02-24-2014 at 02:42 PM.