Originally Posted by Hekse-Mie
In my experience it is not random. It occurs with side-loaded epubs, when a new chapter starts after waking up from sleep-mode.
Actually it is random, at least in my case. I just finished a 300+ page sideloaded book. This bug did not appear once in it. I started a new book, 2 chapters in I had this bug appear again but so far for only that chapter. The chapter that it appeared on was not a new chapter after a wake up but several pages after.