The reason I pre-index assets for the new PreloadManager is for very performant progress calculation during runtime and preloading, and to keep track of the file system hierarchy. It also only loads one asset at a time now, which is overall faster.
Try something in a new project after you update MV to the new version: Make a new project > Make a 30x30 map > Fill with tiles > Playtest and move so the screen scrolls.
If you look at the tiles, do they look odd when they scroll? As in slightly compressed or pixelated oddly? You might have to try with a few different tiles. I'm seeing this bug on Windows 10 at least, but would like confirmation from others.