Reading progress never reaches 100% on any book

Is there a setting I haven’t found that will make this happen? It doesn’t matter if I’m reading on an app that works directly with Grimmory, connects via opds, or whether I’m reading directly in the web reader. Getting to the very end of the last page leaves every single book with <100% reading progress. Even when I manually mark each of the books as “read” so they aren’t cluttering up my Continue Reading section, the incomplete reading percentage persists.