I found a solution to a problem I've been having and wanted to share it. I have a Garmin Forerunner 965 and want to hear audiobooks divided by chapter. I use Epubor to convert the Audible files I own into MP3s that can be loaded to the Garmin watch. My problem was that the chapters were playing in random order.
After lots of trial and error, I discovered that by changing the "Album" field on each file (not the file name) to something shorter it corrected the problem. Hope that helps someone!