I am using Accordance 12.0.1 on a 15" mid 2010 MBP running Sierra 10.12.1. I am also using a 27" Samsung monitor. For some reason when I am in the reading mode and using the external monitor the space bar does not scroll down the text a full screen. Usually with a text it will scroll down just a verse or two, sometimes a little more. The same kind of thing happens when I am in the reading mode with a tool. It may scroll down a couple lines or several lines, I could not discern a pattern. This behavior does not exhibit itself when I use only the built-in display, nor when I am not using the reading mode.
Please note this is not a huge problem for me. I can still scroll up or down with the track pad and I can see what I need to read just fine. One of the things I really like about Accordance is the fact that it is possible to do what one wants to do in various ways. But it would be really nice if I could just move to the next block of reading material with a push of the space bar. Maybe I'm just spoiled!