Issue found!
Options > Visuals > Boxes > Dynamic Box Sizing = true
When it's unchecked, the issue *rarely* happens, rather than literally every time, predictably. Scrolling up is still very hazardous in the "All" category, buy hey, I can actually use Launchbox again.
Edit:
I've since noticed that there is a noticeable additional increase in stability in the "All" category by drastically scaling down the image sizes with the magnification slider on the Button Bar (you can enable the Button Bar with Ctrl+Shift+B, if you currently have it hidden). This shrinks the box front images more than I would like, and causes Launchbox to re-cache all of these images again, and then yet again if I want to scale them back up when I'm done, but might be a crucial step to take if anyone else is dealing with even less stability than I have.
