I've just installed STEP guide too and had the exact same problem.
I found that moving the Grass Cache Fixes plugin as per the screenshot Grass Cache Fixes.png, or just disabling did bring it back but at a distance it was a bit jank. What I've done is leave the plugin above STEP Conflict Resolution and then ran all of Step 5 - LOD Generation again. This does seem to have resolved my issues. It does mean that every time I sort my load order in LOOT, I need to move or disable Grass Cache Fixes plugin / mod.
Sorry, I'm not an expert at mod lists: The ini file in the Step Grass mod, when do ini files get overwritten? I'm wondering if the Grass Cache Fix ini is overwriting the Step ini rather than the other way round?
Or am I going the total wrong direction here