Aloha,
Over the past few days, I've been using scannable A LOT. Long ago, I selected PDF as the default scan option in settings. Yesterday and today, it seems like it's automatically reverting back to AUTO. And then, as a result, it is then choosing PNG as the file format... Of course, I'm not noticing this until after I've saved the file to Google Drive and see it's PNG instead of PDF; resulting in my needing to re-do the whole thing again. I go back to settings and change it back to PDF and it sticks for a while, then it reverts to AUTO again. It seems to happen when I close the APP