[tomsem]

I see blank pages with fixed layout books a bit with iOS (and Scribe), and am never off line. Usually flipping pages back and forward or changing orientation fixes it. With manga you also have option for Z-order panels (double tap to invoke). Have you tried that?

I did borrow the one you reference and it was perfectly okay on my Fire HD10 (it's essentially the same as the Android app, just has text to speech and of course you can purchase things). I would try my pathetic Samsung tablet but it probably needs charging.

To speculate a little, when online it might be syncing location periodically, and maybe that somehow steps on the redraw event. But it should not persistently do this, and as I relate, I can always get the page to display by futzing a little.

Of course, there can also be actual blank pages, particularly when facing pages are part of the design (in landscape you see facing pages with some fixed layout content).