This happens only when HISB is all by itself, not in parallel. It also only happens when my iPad is in the portrait position. When it's in landscape position, the problem doesn't occur.
It also does not occur when using the up arrow (at the bottom of the interface). However, even after I use the arrow to move up a few pages, the problem happens again. For example, when I used the up arrow to go from Acts 27 to Acts 22 and then continued scrolling up by touching the screen, the problem occurs starting from Acts 22.
It seems to be directly related to redrawing the images while scrolling back up. The problem never seems to occur when I scroll down. As I scroll upwards, there is an obvious hesitation when the image is reached. This hesitation occurs less dramatically when scrolling down.
Restarting both Accordance and the iPad doesn't make any difference. I can repeat this problem reliably regardless of chapter. As long as there are at least a couple of images, it doesn't seem to matter where I start. Chapter 27 is only where I first noticed the problem since that was the first time I scrolled up instead of down.
OSX Sierra, Version 10.13.1, iMac (Retina 5K, 27-inch, Late 2014), 4 GHz Intel Core i7, 32 GB 1600 MHz DDR3, AMD Radeon R9 M295X 4096 MB
iPad Pro 10.5, iOS 12.1.1, 512 GB
iPhone 8, iOS 12.1.3, 64 GB