I had the page flipping trouble with my T1 using epub. All the books are 400k+. I decided to wait for a firmware/software update. Yesterday I loaded a .txt format (+500k)and no trouble at all. I tried all ways to crash it and couldn't, fast forward/back with swipe.
Loaded an .epub and, crashed after 20 minutes.
Reset and loaded the .txt. Still OK. I can't figure it out.

I only use swipe, never the buttons.
Edit... The epubs are non DRM